Merge branch 'master' into 9.49.2
hex string in blocks.previous_block_hash
fix sign_tx
Added a Checkpoint at mainnet Block 334000
Merge branch 'master' into 9.49.2
Cherry‐pick 256f310670f201eeaff20ff10d8a4c444d573530
Cherry‐pick 4b3c212
Merge branch 'master' into 9.49.2
Merge branch 'master' into 9.49.2

Conflicts:
	lib/util.py
fix RPC batch
Rename `version.json` to `protocol_changes.json`

- Keep old `version.json` for now, for backwards‐compatibility

- Whitespace
Put Release Date of v9.49.2 in ChangeLog
Merge pull request #510 from CounterpartyXCP/9.49.2

Update `master` to v9.49.2
Merge branch 'master' into develop