Bugfixes: post fetchAll event, invalid hydrator, deep merge on patch

This commit provides a bugfix for 
- #12 
- the note on the doctrine hydrator which can be found at: https://github.com/soliantconsulting/soliantconsulting-apigility/commit/60d76eec072a0ca7d543ec48a6df061ad2a2d045#commitcomment-4817382
- Use recursive merge while Patching (for embedded ODM documents)