DRY up the use of toHex in the project and move it to common

common/common.go

@@ -65,6 +65,15 @@ func DefaultDataDir() string {
 	}
 }
 
+func ToHex(b []byte) string {
+	hex := Bytes2Hex(b)
+	// Prefer output of "0x0" instead of "0x"
+	if len(hex) == 0 {
+		hex = "0"
+	}
+	return "0x" + hex
+}
+
 func FromHex(s string) []byte {
 	if len(s) > 1 {
 		if s[0:2] == "0x" {