cleaned up the DI extension loading mechanism
cleaned up the DI extension loading mechanism

mikeSimonson/DoctrineBundle,Soullivaneuh/DoctrineBundle,gencer/DoctrineBundle,fervo/DoctrineBundle,fabpot/DoctrineBundle,OskarStark/DoctrineBundle,lafourchette/DoctrineBundle,stof/DoctrineBundle,nicolas-grekas/DoctrineBundle,skafandri/DoctrineBundle,gencer/DoctrineBundle,Soullivaneuh/DoctrineBundle,fabpot/DoctrineBundle,skafandri/DoctrineBundle,chrisguitarguy/DoctrineBundle,doctrine/DoctrineBundle,dunglas/DoctrineBundle,javiereguiluz/DoctrineBundle,hacfi/DoctrineBundle,javiereguiluz/DoctrineBundle,chrisguitarguy/DoctrineBundle,mikeSimonson/DoctrineBundle,hacfi/DoctrineBundle,nicolas-grekas/DoctrineBundle,fervo/DoctrineBundle,OskarStark/DoctrineBundle,hason/DoctrineBundle,hason/DoctrineBundle