Update node and apply some fixes

- Node
	- Load Coordinator Fee Account from config
		- Sign the AccountCreationMsg to generate the
		  AccountCreationAuth
		- Resolve #465
	- Wait for synchronizer termination before stopping coordinator to avoid
	  getting stuck when closing in the following case:
		- The coordinator stops reading the synchronizer msg channel,
		  and the node gets stuck sending a message to that channel.
- Common
	- Move account creation auth signature code to common.
	- Update RollupConstInputSHAConstantBytes
- Coordinator
	- Set batch status in the debug file
	- Propagate SCVariables on reorg
	- Pipeline: Get SCVariables updates
		- Resolve #457
	- Fix off by 1 error in Pipeline.shouldL1L2Batch() (which shouldn't have
	  caused any problem, but it was not right)
- KVDB
	- Delete future checkpoints after reset
	- In `ResetFromSynchronizer`, remove all checkpoints first, and follow
	  the same logic as `reset()`.
- Cli
	- Add command to generate a BabyJubJub key pair (to be used for the
	  Coordinator Fee Account)
- Node
	- Adjust example config `Coordinator.L1BatchTimeoutPerc` to avoid
	  missing the L1Batch deadline with the following setup:
		- a block is mined every 2 seconds
		- single proof server that takes 2 seconds to calculate a proof
- TxProcessor
	- Close temporary pebble used for the exit tree after usage.
		- Resolve #463

cli/node/cfg.buidler.toml

@@ -40,12 +40,20 @@ TokenHEZName = "Hermez Network Token"
 
 [Coordinator]
 # ForgerAddress = "0x05c23b938a85ab26A36E6314a0D02080E9ca6BeD" # Non-Boot Coordinator
+# ForgerAddressPrivateKey = "0x30f5fddb34cd4166adb2c6003fa6b18f380fd2341376be42cf1c7937004ac7a3"
 ForgerAddress = "0xb4124ceb3451635dacedd11767f004d8a28c6ee7" # Boot Coordinator
+# ForgerAddressPrivateKey = "0xa8a54b2d8197bc0b19bb8a084031be71835580a01e70a45a13babd16c9bc1563"
 ConfirmBlocks = 10
-L1BatchTimeoutPerc = 0.6
+L1BatchTimeoutPerc = 0.4
 ProofServerPollInterval = "1s"
 SyncRetryInterval = "1s"
 
+[Coordinator.FeeAccount]
+Address = "0x56232B1c5B10038125Bc7345664B4AFD745bcF8E"
+# PrivateKey = "0x3a9270c020e169097808da4b02e8d9100be0f8a38cfad3dcfc0b398076381fdd"
+BJJ = "0x1b176232f78ba0d388ecc5f4896eca2d3b3d4f272092469f559247297f5c0c13"
+# BJJPrivateKey = "0xb556862fb60e7cf4c0a8a7f44baf2ab06a4c90ac39decc4eef363b6142d07a34"
+
 [Coordinator.L2DB]
 SafetyPeriod = 10
 MaxTxs       = 512
@@ -71,10 +79,11 @@ NLevels = 32
 [Coordinator.EthClient]
 ReceiptTimeout      = "60s"
 ReceiptLoopInterval = "500ms"
-
 CheckLoopInterval = "500ms"
 Attempts = 8
 AttemptsDelay = "200ms"
+CallGasLimit = 300000
+GasPriceDiv = 100
 
 [Coordinator.EthClient.Keystore]
 Path = "/tmp/iden3-test/hermez/ethkeystore"