fixed problems with joined inheritance and composite keys

SchemaTool now creates all Id columns not just only the first one.
Insert statement for child entity now contains parameter for additional key columns only once.
inheritance with composite keys

added tests for single table inheritance
Strong typehinting to avoid incorrect constructor params
Fixing incorrect constructor params for PreFlushEventArgs
Using composer autoloader for the test suite
Adding warnings about deprecation of GIT, TAR and PEAR autoloading
Fixed wrong return types in documentation.
Unit tests: cleaned up outdated / unused / commented out code.
Merge pull request #578 from BenMorel/docfix

Fix for wrong return types in documentation.
Merge pull request #569 from Ocramius/hotfix/pre-flush-event-args-params

Hotfix/pre flush event args params
Fix test failing when memcache extension is installed, but memcache server isnt.
[DDC-2256] Cleanup patch, move dependency on EntityManager out of ResultSetMapping and let AbstractQuery perform the translation.
Merge pull request #570 from Ocramius/cleanup/submodules-removal

Deprecation of PEAR/GIT/TAR autoloading
Proxy generation as of doctrine/common#168 - DCOM-96
Adding fix and tests for DDC-1734
Cleaning up logic of the proxy factory by moving closure generation to own private methods
Merge pull request #406 from Ocramius/DCOM-96

[DCOM-96] Moving proxy generation and autoloading to common
Fix dropping the theme folder.
Add vendor to .gitignore, add composer.lock and some weird submodule change
Remove mentions of PEAR installation method, remove code.