- Debug Batch File
    - Add details about why a batch is scheduled to be L1Batch or regular
    - Add timestamps in time and blockNumber of important events
    - Use a different naming for the files (batchNum + timestamp)
- Coordinator:
    - To make decisions and store debug info, always use the current block that
      is being mined, instead of the last mined block

Previously the coordinator was erroneously using Slot.BatchesLen to determine
when anyone can forge.  The correct behaviour is implmenented with the boolean
flag `ForgerCommitment`, that is set to true only when there's a batch before
the deadline within a slot.

Delete Slot.BatchesLen, and the synchronization code of this value from the
Synchronizer, as this is not needed

Update usage of `*babyjub.PublicKey` to `babyjub.PublicKeyComp`
- when the key is not defined, internally is used `babyjub.EmptyBJJComp`, which is a `[32]byte` of zeroes of type `babyjub.PublicKeyComp`
- the API continues returning `nil` when the key is not defined

Previously the Synchronizer required the initial variables of the smart
contracts to be passed as a configuration parameter (that the node took from
the configuration file).  The same applied to the blockNumber.

The last update of the smart contracts introduced events for each smart
contract constructor (initializer), which allows querying the initial variables
as well as the initial block number for each smart contract.

Now the synchronizer uses this information, and thus the initial variables and
the starting block numbers have been removed from the configuration.

- API:
	- Replace `emergencyModeStaringTime` by `emercengyModeStartingBlock`
- Synchronizer:
	- Track emergency mode starting block
- cli/node
	- Add working coordinator config
- coordinator:
	- Retry handler for synchronizer stats in case of error (instead of
	  waiting for the next block to try again)
	- On init, trigger an initial call to the handler for synced block
	  before waiting for the synchronizer, to force the coordinator to start
	  its logic even if there's no new block right after the node has been
	  started (very useful for running in testnet where the frequency of
	  blocks is variable)
	- Merge Msg for synced block and updated vars into one: `MsgSyncBlock`.

- API
	- When updating network info, handle cases where no batches exists and
	  where no forgers exists
- cli/node
	- Update `cfg.buidler.toml` config file to a working version
- common
	- Add new smart contract structs and extend some existing ones to
	  reflect updates regarding events from the smart contracts
- SQL
	- Add new tables and extend existing ones to reflect updates regarding
	  events from the smart contracts
- db/historydb
	- Add functions to insert new smart contract events data
	- Fix unclosed rows that led to inconsistent sql driver state (replace
	  NamedQuery by NamedExec).  This fixes the error:
	  `pq: unexpected Parse response 'C'`
- db/l2db
	- Close rows after usage
- eth
	- In Rollup event, introduce a new UpdateBucketsParameter when there's a
	  SafeMode event, with `SafeMode = true`
- synchronizer
	- synchronize new events
	- avoid calling `auction.CanForge` before the genesisBlock to avoid
	  getting a revert.

- Common
	- Move ErrTODO and ErrDone to common for usage where needed.
- Coordinator
	- Move prover types to prover package
	- Handle reorgs, stopping the pipeline when necessary
	- Handle ethereum transaction errors by stopping the pipeline
	- In case of ethereum transaction revert, check for known revert causes
	  (more revert causes can be added to handle more cases)
	- Fix skipped transactions in TxManager confirmation logic
	- Cancel and wait for provers to be ready
	- Connect L2DB to:
		- purge l2txs due to timeout
		- mark l2txs at the different states
	- Connect HistoryDB to query L1UserTxs to forge in an L1Batch
- L2DB
	- Skip update functions when the input slices have no values (to avoid a
	  query with no values that results in an SQL error)
- StateDB
	- In LocalStateDB, fix Reset when mt == nil
- Prover (new package)
	- Rename the interface to Prover
	- Rename the mock struct to Mock
	- Extend Prover interface methods to provide everything required by the
	  coordinator
	- Begin implementing required http client code to interact with server
	  proof (not tested)
- Synchronizer:
	- Add LastForgeL1TxsNum to Stats
- Test/Client
	- Update Auction logic to track slots in which there's no forge during
	  the time before the deadline (following the solidity implementation)

- Common:
	- Rename Block.EthBlockNum to Block.Num to avoid unneeded repetition
- API:
	- Add UpdateNetworkInfoBlock to update just block information, to be
	  used when the node is not yet synchronized
- Node:
	- Call API.UpdateMetrics and UpdateRecommendedFee in a loop, with
	  configurable time intervals
- Synchronizer:
	- When mapping events by TxHash, use an array to support the possibility
	  of multiple calls of the same function happening in the same
	  transaction (for example, a smart contract in a single transaction
	  could call withdraw with delay twice, which would generate 2 withdraw
	  events, and 2 deposit events).
	- In Stats, keep entire LastBlock instead of just the blockNum
	- In Stats, add lastL1BatchBlock
	- Test Stats and SCVars
- Coordinator:
	- Enable writing the BatchInfo in every step of the pipeline to disk
	  (with JSON text files) for debugging purposes.
	- Move the Pipeline functionality from the Coordinator to its own struct
	  (Pipeline)
	- Implement shouldL1lL2Batch
	- In TxManager, implement logic to perform several attempts when doing
	  ethereum node RPC calls before considering the error. (Both for calls
	  to forgeBatch and transaction receipt)
	- In TxManager, reorganize the flow and note the specific points in
	  which actions are made when err != nil
- HistoryDB:
	- Implement GetLastL1BatchBlockNum: returns the blockNum of the latest
	  forged l1Batch, to help the coordinator decide when to forge an
	  L1Batch.
- EthereumClient and test.Client:
	- Update EthBlockByNumber to return the last block when the passed
	  number is -1.

- API:
	- Modify the constructor so that hardcoded rollup constants don't need
	  to be passed (introduce a `Config` and use `configAPI` internally)
- Common:
	- Update rollup constants with proper *big.Int when required
	- Add BidCoordinator and Slot structs used by the HistoryDB and
	  Synchronizer.
	- Add helper methods to AuctionConstants
	- AuctionVariables: Add column `DefaultSlotSetBidSlotNum` (in the SQL
	  table: `default_slot_set_bid_slot_num`), which indicates at which
	  slotNum does the `DefaultSlotSetBid` specified starts applying.
- Config:
	- Move coordinator exclusive configuration from the node config to the
	  coordinator config
- Coordinator:
	- Reorganize the code towards having the goroutines started and stopped
	  from the coordinator itself instead of the node.
	- Remove all stop and stopped channels, and use context.Context and
	  sync.WaitGroup instead.
	- Remove BatchInfo setters and assing variables directly
	- In ServerProof and ServerProofPool use context instead stop channel.
	- Use message passing to notify the coordinator about sync updates and
	  reorgs
	- Introduce the Pipeline, which can be started and stopped by the
	  Coordinator
	- Introduce the TxManager, which manages ethereum transactions (the
	  TxManager is also in charge of making the forge call to the rollup
	  smart contract).  The TxManager keeps ethereum transactions and:
	  	1. Waits for the transaction to be accepted
		2. Waits for the transaction to be confirmed for N blocks
	- In forge logic, first prepare a batch and then wait for an available
	  server proof to have all work ready once the proof server is ready.
	- Remove the `isForgeSequence` method which was querying the smart
	  contract, and instead use notifications sent by the Synchronizer to
	  figure out if it's forging time.
	- Update test (which is a minimal test to manually see if the
	  coordinator starts)
- HistoryDB:
	- Add method to get the number of batches in a slot (used to detect when
	  a slot has passed the bid winner forging deadline)
	- Add method to get the best bid and associated coordinator of a slot
	  (used to detect the forgerAddress that can forge the slot)
- General:
	- Rename some instances of `currentBlock` to `lastBlock` to be more
	  clear.
- Node:
	- Connect the API to the node and call the methods to update cached
	  state when the sync advances blocks.
	- Call methods to update Coordinator state when the sync advances blocks
	  and finds reorgs.
- Synchronizer:
	- Add Auction field in the Stats, which contain the current slot with
	  info about highest bidder and other related info required to know who
	  can forge in the current block.
	- Better organization of cached state:
		- On Sync, update the internal cached state
		- On Init or Reorg, load the state from HistoryDB into the
		  internal cached state.

- In exit table, `instant_withdrawn`, `delayed_withdraw_request`, and
  `delayed_withdrawn` were referencing batch_num.  But these actions happen
  outside a batch, so they should reference a block_num.
- Process delayed withdrawns:
    - In Synchronizer, first match a Rollup delayed withdrawn request, with the
      WDelayer deposit (via TxHash), and store the owner and token associated
      with the delayed withdrawn.
    - In HistoryDB: store the owner and token of a delayed withdrawal request
      in the exit_tree, and set delayed_withdrawn when the withdraw is done in
      the WDelayer.
- Update dependency of sqlx to master
    - Last release of sqlx is from 2018 October, and it doesn't support
      `NamedQuery` with a slice of structs, which is used in this commit.

- node:
    - Extend config to add initial variables of the smart contracts used as
      defaults before they are changed via events.
    - In stopped channels, set size 1 so that panics are not witheld until the
      node stops completely.
- common:
    - In Smart Contract variables, comment:
      - `WDelayerVariables.HermezRollupAddress` because it's not needed.
      - `RollupVariables.Buckets` because there are no events for it, and for
        now it's not used.
- historydb:
    - Add functions to get and set smart contract variables.
- db:
    - Add `Rollback` function in `utils.go` to reduce boilerplate in sql
      transaction rollbacks in defers in db functions.
    - Update `rollup_vars` and `auction_vars` (renamed from `consensus_vars`)
      table, and add `wdelayer_vars` table.
- synchronizer:
    - Synchronize WDelayer
    - Handle SC variables properly
- test/ethclient:
    - Add essential implementation of WDelayer

- Move smart contract constants and structs for variables to
  common/{ethrollup.go, ethauction.go, ethwdelayer.go}:
    - This removes repeated code of the structs for variables
    - Allows reusing the constants and variables from all modules without
      import cycles
- Remove unused common/scvars.go
- In common.BlockData, split data from each smart contract into a sepparate
  field (Rollup, Auction, WDelayer).  This affects the structures that til uses
  as output, and HistoryDB in the AddBlockSCData.
- In Synchronizer:
    - Pass starting block of each smart contract as config, instead of
      incorrectly using the genesis block found in the acution constant (which
      has a very different meaning)
    - Use variable structs from common instead of an internal copy
    - Synchronize more stuff (resolve some TODOs)
    - Fix some issues found after initial testing with ganache
- In eth:
    - In auction.go: Add method to get constants
    - Update README to use ganache instead of buidlerevm as local blockchain
      for testing
    - Update env variables and test vectors to pass the tests with the
      deployment in the ganache testnet.
    - Use ethereum keys derived from paths (hdwallet) in testing to avoid
      hardcoding private keys and generate the same keys from a mnemonic used
      in the ganache tesnet.

- Test L1UserTxs in Synchronizer
- Test Batches in Synchronizer
- Add last_idx in `TABLE batch` in HistoryDB
- Minor updates in til to satisfy blockchain constraints

- Implement SlicePtrsToSlice and use it in all `meddler.QueryAll` sql db functions to always return []Foo instead of []*Foo

- Implement new TxID spec that distinguishes L1UserTx and L1CoordinatorTx
- Replace some type []*Foo by []Foo
- Fix HistoryDB & L2DB bug: in case of error, a rollback was applied and the returned error was nil
- Reorder inserts in historydb.NewHistoryDB() to follow foreign key dependencies
- Add initial synchronizer test with test.Client (for now, only tested l1UserTxs, blocks, addToken)
- Update L1UserTx event in test.Client

* WIP: rebase

* Make nullable fields use pointers

Change endianness to BigEndian (ಥ﹏ಥ), spec has been updated to achieve
compatibility with js & smart contracts & circuits implementations.