update Symfony2 dependency
update Symfony2 dependency

stof/Silex,mTorres/Silex,akucherevskiy/developex_test,lokhman/Silex,peterkokot/Silex,JPry/Silex,stof/Silex,mTorres/Silex,romainneutron/Silex,akucherevskiy/developex_test,Seldaek/Silex,mathroc/Silex,GromNaN/Silex,Tobion/Silex,tcx1000/Silex,RayRutjes/Silex,RayRutjes/Silex,fabpot/Silex,peterkokot/Silex,lyrixx/Silex,naderman/Silex,fhinkel/Silex,fhinkel/Silex,Incognito/silex-fork,lyrixx/Silex,Tobion/Silex,arduanov/Silex,cgsmith/Silex,silexphp/Silex,cesarmarinhorj/Silex,mathroc/Silex,beealone/Silex,fabpot/Silex,tcx1000/Silex,jdreesen/Silex,beealone/Silex,romainneutron/Silex,peterkokot/Silex,SpacePossum/Silex,plotek/Silex,CarsonF/Silex,Xephi/Silex,SanderKnape/Silex,akucherevskiy/developex_test,Seldaek/Silex,JPry/Silex,cesarmarinhorj/Silex,mmauri04/Silex,jdreesen/Silex,SpacePossum/Silex,plotek/Silex,cgsmith/Silex,SanderKnape/Silex,lyrixx/Silex,GromNaN/Silex,romainneutron/Silex,Incognito/silex-fork,CarsonF/Silex,GromNaN/Silex,naderman/Silex,lokhman/Silex,Tobion/Silex,stof/Silex,gencer/Silex,naderman/Silex,Xephi/Silex,mmauri04/Silex,CarsonF/Silex,arduanov/Silex