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

common/accountcreationauths.go

@@ -49,12 +49,34 @@ func (a *AccountCreationAuth) HashToSign(chainID uint16,
 	return ethCrypto.Keccak256Hash(b).Bytes(), nil
 }
 
+// Sign signs the account creation authorization message using the provided
+// `signHash` function, and stores the signaure in `a.Signature`.  `signHash`
+// should do an ethereum signature using the account corresponding to
+// `a.EthAddr`.  The `signHash` function is used to make signig flexible: in
+// tests we sign directly using the private key, outside tests we sign using
+// the keystore (which never exposes the private key).
+func (a *AccountCreationAuth) Sign(signHash func(hash []byte) ([]byte, error),
+	chainID uint16, hermezContractAddr ethCommon.Address) error {
+	hash, err := a.HashToSign(chainID, hermezContractAddr)
+	if err != nil {
+		return err
+	}
+	sig, err := signHash(hash)
+	if err != nil {
+		return err
+	}
+	sig[64] += 27
+	a.Signature = sig
+	a.Timestamp = time.Now()
+	return nil
+}
+
 // VerifySignature ensures that the Signature is done with the EthAddr, for the
 // chainID and hermezContractAddress passed by parameter
 func (a *AccountCreationAuth) VerifySignature(chainID uint16,
 	hermezContractAddr ethCommon.Address) bool {
 	// Calculate hash to be signed
-	msg, err := a.HashToSign(chainID, hermezContractAddr)
+	hash, err := a.HashToSign(chainID, hermezContractAddr)
 	if err != nil {
 		return false
 	}
@@ -64,7 +86,7 @@ func (a *AccountCreationAuth) VerifySignature(chainID uint16,
 	sig[64] -= 27
 
 	// Get public key from Signature
-	pubKBytes, err := ethCrypto.Ecrecover(msg, sig[:])
+	pubKBytes, err := ethCrypto.Ecrecover(hash, sig[:])
 	if err != nil {
 		return false
 	}