Merge pull request #139 from jweber/master

Added support for the has_fields document manipulation operator
Update release notes w/ PR #139.
Add tests for StringDatumConverter.
Add tests for BoolDatumConverter
Add tests for DoubleDatumConverter
Add TupleConverter and ArrayConverter tests.
Add exception coverage to Bool, Double and String converters.
Add AggregateDatumConverter tests.
Add AnonymousTypeConverter tests.
Formatting cleanups.
Add null datum test case.
Revert accidental change.
Cleanup RethinkDb namespace

Remove components from RethinkDb namespace that aren't referenced
constantly in normal RethinkDb operations, like DatumConverters,
Logging stuff.
Move DatumHelpers to test assembly.
Merge pull request #140 from tetious/datumconverter-tests

Unit tests for IDatumConverter implementations, fixes #60
Merge branch 'master' into cleanup_RethinkDb_namespace
Continue namespace cleanup
Merge pull request #141 from mfenniak/cleanup_RethinkDb_namespace

Cleanup RethinkDb namespace
Add PR #140, PR #141, and issue #60 to release notes.
Initial implementation of connection pooling