Allow query parameters starting with an underscore
Add test for query paremeters starting with underscore
Modified Hydrators to be per-query instances instead of a singleton-like approach.
Kept BC.
Merge pull request #738 from doctrine/VolatileQueryHydrators

Modified Hydrators to be per-query instances instead of a singleton-like approach
Merge pull request #717 from hackedd/patch-1

Allow query parameters starting with an underscore
fix DDC-2579
Merge pull request #739 from FabioBatSilva/DDC-2579

Fix DDC-2579
Synchronized support of FilterCollection with ODM by adding missing method.
Merge pull request #740 from doctrine/FilterCollectionEnhancement

Synchronized support of FilterCollection with ODM by adding missing method