Finished first parts of SELECT support. Two test cases added and passing. Introduced the concept of DCTRN in queryComponent. Added concept of queryField, which validates for already defined fields in SELECT.

Merged all identity maps into one in the unitofwork. identity map now properly works with hierarchies.

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.