StateDB ZKInputs generation compatible with circom

- Add SignatureConstant to L1Tx.TxCompressedData
- ZKInputs generation works initial version working and compatible with circom Hermez circuit
    - Lots of small updates for circuits compatibility
- Update version (with new changes) of `go-iden3-crypto` & `go-merkletree`

common/l1tx.go

@@ -167,8 +167,9 @@ func (tx L1Tx) TxCompressedData() (*big.Int, error) {
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
+
 	var b [31]byte
-	// b[0:7] empty: no fee neither nonce
+	// b[0:7] empty: no ToBJJSign, no fee, no nonce
 	copy(b[7:11], tx.TokenID.Bytes())
 	copy(b[11:13], amountFloat16.Bytes())
 	toIdxBytes, err := tx.ToIdx.Bytes()
@@ -181,8 +182,8 @@ func (tx L1Tx) TxCompressedData() (*big.Int, error) {
 		return nil, tracerr.Wrap(err)
 	}
 	copy(b[19:25], fromIdxBytes[:])
-	copy(b[25:27], []byte{0, 1}) // TODO this will be generated by the ChainID config parameter
-	// b[27:] empty: no signature
+	copy(b[25:27], []byte{0, 0}) // TODO this will be generated by the ChainID config parameter
+	copy(b[27:31], SignatureConstantBytes[:])
 
 	bi := new(big.Int).SetBytes(b[:])
 	return bi, nil