ZKInput with L2Txs compatible with circom circuits

- Til
  - update Til users BJJ key generation for better js tests
    compatibility
- Common
  - PoolL2Tx to L2Tx use AuxToIdx in case that ToIdx is 0
  - Update ZKInputs parameter descriptions
- TxProcessor
  - Fix AccumulatedFees in case that there is no CoordIdx for that token
  - Fix zki.NewExit usage
  - Use same order for AccumulatedFees & FeeIdx & FeePlanTokens
  - Add Nonce usage to ExitLeafs
  - Update TestZKInput6 and check its compatibility with circom Hermez
circuits

test/til/sets.go

@@ -224,7 +224,6 @@ CreateAccountDeposit(1) C: 0
 // close Block:0, Batch:1
 > batchL1 // freeze L1User{2}, forge L1Coord{0}
 // Expected balances:
-//     Coord(0): 0, Coord(1): 0
 //     C(0): 0
 
 CreateAccountDeposit(1) A: 500
@@ -232,14 +231,12 @@ CreateAccountDeposit(1) A: 500
 // close Block:0, Batch:2
 > batchL1 // freeze L1User{1}, forge L1User{2}
 // Expected balances:
-//     Coord(0): 0, Coord(1): 0
 //     A(0): 500
 //     C(0): 0, C(1): 0
 
 // close Block:0, Batch:3
 > batchL1 // freeze L1User{nil}, forge L1User{1}
 // Expected balances:
-//     Coord(0): 0, Coord(1): 0
 //     A(0): 500, A(1): 500
 //     C(0): 0
 
@@ -253,7 +250,6 @@ CreateAccountDeposit(0) D: 800
 // close Block:0, Batch:5
 > batchL1 // freeze L1User{1}, forge L1User{1}
 // Expected balances:
-//     Coord(0): 0, Coord(1): 0
 //     A(0): 600, A(1): 500
 //     B(0): 400
 //     C(0): 0

test/til/txs.go

@@ -2,9 +2,9 @@ package til
 
 import (
 	"crypto/ecdsa"
+	"encoding/binary"
 	"fmt"
 	"math/big"
-	"strconv"
 	"strings"
 	"time"
 
@@ -694,7 +694,9 @@ func (tc *Context) generateKeys(userNames []string) {
 		}
 		// babyjubjub key
 		var sk babyjub.PrivateKey
-		copy(sk[:], []byte(strconv.Itoa(i))) // only for testing
+		var iBytes [8]byte
+		binary.LittleEndian.PutUint64(iBytes[:], uint64(i))
+		copy(sk[:], iBytes[:]) // only for testing
 
 		// eth address
 		var key ecdsa.PrivateKey

test/til/txs_test.go

@@ -1,14 +1,34 @@
 package til
 
 import (
+	"encoding/hex"
+	"fmt"
 	"math/big"
 	"testing"
 
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
+func TestGenerateKeys(t *testing.T) {
+	tc := NewContext(0, common.RollupConstMaxL1UserTx)
+	usernames := []string{"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k"}
+	tc.generateKeys(usernames)
+	debug := false
+	if debug {
+		for i, username := range usernames {
+			fmt.Println(i, username)
+			sk := crypto.FromECDSA(tc.Users[username].EthSk)
+			fmt.Println("	eth_sk", hex.EncodeToString(sk))
+			fmt.Println("	eth_addr", tc.Users[username].Addr)
+			fmt.Println("	bjj_sk", hex.EncodeToString(tc.Users[username].BJJ[:]))
+			fmt.Println("	bjj_pub", tc.Users[username].BJJ.Public().Compress())
+		}
+	}
+}
+
 func TestGenerateBlocksNoBatches(t *testing.T) {
 	set := `
 		Type: Blockchain