Breaking changes to the Java driver

[NotJustAnna]

This PR tracks experimental changes for the official rethinkdb-java driver.

Implemented changes

• Updated compile and test dependencies
• Replaced json-simple with Jackson
  • JSON manipulation is done with plain Java collections
• Replaced java.util.Optional usage with @Nullable annotations
• Fixes Util.toReqlAst() wrongly resetting the remaining depth.
• ReqlAst improvements
  • Support for Jackson's TypeReference<T> on ReqlAst.run()
  • ReqlAst.runAsync(): Asynchronous result
  • ReqlAst.toString() pretty-prints the AST
• Added generics to MapObject
• Connection rewrite
  • The connection and the response pump are now wrapped in an interface and custom factories can be set in the builder, with the default factories implemented at DefaultConnectionFactory
  • The handshake is entirely handled by the HandshakeProtocol class instead of the connection socket.
  • Connection.noreplyWaitAsync(): Asynchronous noreplyWait
  • Added Connection.server() and async variance (Implements Add server_info() command #14)
  • Added support for db-urls (Implements python drivers support db-url schemas rethinkdb#4101)
• Cursor was deleted and replaced with Result
  • ReqlAsr.run() always returns Result<T>, which covers all result types and implements Iterator<T> and Iterable<T>
  • toList(), collect(), stream(), parallelStream() methods
  • Fetch modes for partial sequences
  • If enabled, unwraps atom responses which are lists (Result<List<T>> is unwrapped to Result<T>)
  • Exposed Response's Profile into the builder
  • Pending, leaking Results can be closed from the Connection
• Added r.pathspec(...) (Implements Implement r.pathspec(...) #16)
• Renamed methods with weird names and inlined factory methods and Response Builder
• Util.toReqlAst() now properly serializes primitive arrays and other Collections as well.
• Documentation for most public methods
• A lot of small performance improvements.

Partially implemented

• RethinkDB-specific classes (Make POJOs for RethinkDB-specific objects. #18 - Probably will be implemented in a separate PR)
  • Currently implemented: CoerceType

Notes

1. Code which use Connection, Cursor and the old dynamic return type of .run breaks, but those classes got full documentation of the new usage.

2. All tests doesn't compile. Root tests may need manual rewrite while Generated tests need Python scripts need rewrite to generate new valid tests. Tests now compile by patching TestingCommon to generate expected behaviour.

[NotJustAnna]

Enum deserialization should be implemented once #9 is merged. Merged and implemented.

[NotJustAnna]

If #12 gets merged, Cursors will be removed in favour of reactive flows.

UPDATE: Since 037429c, it now has a reactive Connection implementation, with detached Socket and Response Pump, if you want to write your custom implementation of the socket or integrate the response pump into your main service, say, Spring or Vert.x

Reactive streams was dropped due to their non-null behaviour.

[NotJustAnna]

rethinkdb/rethinkdb#4101 implemented on commits d214109 and e56f344.