Update doc/usage.rst
Update doc/usage.rst

I'm new to http methods other than GET and POST and spent a good few minutes searching google for PUT DELETE... So I thought I'd separate them somehow in the docs
peterkokot/Silex,romainneutron/Silex,SpacePossum/Silex,JPry/Silex,tcx1000/Silex,plotek/Silex,gencer/Silex,naderman/Silex,mTorres/Silex,arduanov/Silex,akucherevskiy/developex_test,silexphp/Silex,Xephi/Silex,JPry/Silex,jdreesen/Silex,SanderKnape/Silex,CarsonF/Silex,mathroc/Silex,Tobion/Silex,Tobion/Silex,beealone/Silex,fabpot/Silex,RayRutjes/Silex,Tobion/Silex,lokhman/Silex,CarsonF/Silex,fhinkel/Silex,cesarmarinhorj/Silex,mTorres/Silex,mmauri04/Silex,cgsmith/Silex,arduanov/Silex,cesarmarinhorj/Silex,lokhman/Silex,romainneutron/Silex,Xephi/Silex,akucherevskiy/developex_test,GromNaN/Silex,plotek/Silex,mathroc/Silex,RayRutjes/Silex,peterkokot/Silex,naderman/Silex,romainneutron/Silex,fabpot/Silex,fhinkel/Silex,akucherevskiy/developex_test,jdreesen/Silex,SanderKnape/Silex,GromNaN/Silex,mmauri04/Silex,beealone/Silex,SpacePossum/Silex,Incognito/silex-fork,CarsonF/Silex,cgsmith/Silex,tcx1000/Silex,peterkokot/Silex,Incognito/silex-fork,GromNaN/Silex,naderman/Silex