Update missing parts, improve til, and more

- Node
	- Updated configuration to initialize the interface to all the smart
	  contracts
- Common
	- Moved BlockData and BatchData types to common so that they can be
	  shared among: historydb, til and synchronizer
	- Remove hash.go (it was never used)
	- Remove slot.go (it was never used)
	- Remove smartcontractparams.go (it was never used, and appropriate
	  structs are defined in `eth/`)
	- Comment state / status method until requirements of this method are
	  properly defined, and move it to Synchronizer
- Synchronizer
	- Simplify `Sync` routine to only sync one block per call, and return
	  useful information.
	- Use BlockData and BatchData from common
	- Check that events belong to the expected block hash
	- In L1Batch, query L1UserTxs from HistoryDB
	- Fill ERC20 token information
	- Test AddTokens with test.Client
- HistryDB
	- Use BlockData and BatchData from common
	- Add `GetAllTokens` method
	- Uncomment and update GetL1UserTxs (with corresponding tests)
- Til
	- Rename all instances of RegisterToken to AddToken (to follow the smart
	  contract implementation naming)
	- Use BlockData and BatchData from common
		- Move testL1CoordinatorTxs and testL2Txs to a separate struct
		  from BatchData in Context
	- Start Context with BatchNum = 1 (which the protocol defines to be the
	  first batchNum)
	- In every Batch, set StateRoot and ExitRoot to a non-nil big.Int
	  (zero).
	- In all L1Txs, if LoadAmount is not used, set it to 0; if Amount is not
	  used, set it to 0; so that no *big.Int is nil.
	- In L1UserTx, don't set BatchNum, because when L1UserTxs are created
	  and obtained by the synchronizer, the BatchNum is not known yet (it's
	  a synchronizer job to set it)
	- In L1UserTxs, set `UserOrigin` and set `ToForgeL1TxsNum`.

common/batch.go

@@ -16,11 +16,11 @@ type Batch struct {
 	EthBlockNum   int64                `meddler:"eth_block_num"` // Ethereum block in which the batch is forged
 	ForgerAddr    ethCommon.Address    `meddler:"forger_addr"`   // TODO: Should this be retrieved via slot reference?
 	CollectedFees map[TokenID]*big.Int `meddler:"fees_collected,json"`
-	StateRoot     Hash                 `meddler:"state_root"`
+	StateRoot     *big.Int             `meddler:"state_root,bigint"`
 	NumAccounts   int                  `meddler:"num_accounts"`
-	ExitRoot      Hash                 `meddler:"exit_root"`
+	ExitRoot      *big.Int             `meddler:"exit_root,bigint"`
 	ForgeL1TxsNum *int64               `meddler:"forge_l1_txs_num"` // optional, Only when the batch forges L1 txs. Identifier that corresponds to the group of L1 txs forged in the current batch.
-	SlotNum       SlotNum              `meddler:"slot_num"`         // Slot in which the batch is forged
+	SlotNum       int64                `meddler:"slot_num"`         // Slot in which the batch is forged
 	TotalFeesUSD  *float64             `meddler:"total_fees_usd"`
 }