RethinkDB 2.4 Release

[bchavez]

RethinkDB 2.4 is released and back in full swing. C# driver will need to be updated.

https://rethinkdb.com/blog/2.4.0-release
https://github.com/rethinkdb/rethinkdb/releases/tag/v2.4.0

Tasks

• Update proto files, regenerate AST for bitwise operators.
• Implement write-hooks
• Re-import YAML test harness and re-run test battery against 2.4.
• And finally, all 2.4 milestones must be completed.

See commit history for October 25, 2019 here:
https://github.com/rethinkdb/rethinkdb-java/commits/master