1. Closes#840: added Nonce field to transaction.Transaction and
removed Nonce field from transaction.MinerTx
2. Added following methods to different tx types:
- NewMinerTx()
- NewMinerTxWithNonce(...)
- NewEnrollmentTx(...)
- NewIssueTx()
- NewPublishTx(...)
- NewRegisterTx(...)
- NewStateTx(...)
in order to avoid code duplication when new transaction is created.
3. Commented out test cases where binary transaction/block are used.
These test cases marked with `TODO NEO3.0: Update binary` and need to be
updated.
4. Updated other tests
5. Added constant Nonce to GoveringTockenTx, UtilityTokenTx and genesis
block to avoid data variability. Also marked with TODO.
Frequently one needs to check if struct serializes/deserializes
properly. This commit implements helpers for such cases including:
1. JSON
2. io.Serializable interface
