- fixed issue with _primary being null in sharded systems.
- fix issue with mapreduce command name for sharded systems.
fixing tests against sharded systems.
CSHARP-753: Implemented >, >=, <, <= comparisons against array size
CSHARP-753: Added SizeLessThan and SizeLessThanOrEqual.
CSHARP-753: Added unit tests for List length queries.