Refactorings along with a speed improvement on the Hydrator when processing joined resultsets. Other minor tweaks.

Ported fix for #929 from 0.10 to trunk. Testcase needs to be ported later since the behavior implementation is not useable in trunk atm.

merged fix for #912 from 0.10 to trunk (turned out it was not broken in trunk but i merged the patch & testcase anyway. Other refactorings.

refactorings, a bug fix (#786) and improved performance for the hydration of results from polymorphic queries.

moved managed record/entity handling to the UnitOfWork. identity maps are the next. started to remove obsolete table stuff.

Removed support to imbricated query added yesterday (which fixed ticket #782). The same thing could be easily achieved without need of Doctrine support, as mentioned in comments. Dev team decided to drop this support for now, but are considering for 1.0

made sure every caller of getIdentifier can handle an array. getIdentifier now always returns an array.