updated macro documentation to warn about a hack that won't work anymore in Twig 2.x
updated macro documentation to warn about a hack that won't work anymore in Twig 2.x

phansys/Twig,derickr/Twig,huang53798584/Twig,Rvanlaak/Twig,znerol/Twig,moltin/Twig,hason/Twig,hason/Twig,moltin/Twig,hason/Twig,Rvanlaak/Twig,moufmouf/Twig,gamernetwork/Twig,nicolas-grekas/Twig,nicolas-grekas/Twig,twigphp/Twig,craue/Twig,huang53798584/Twig,fsw/Twig,robregonm/Twig,loi-chuanoi/Twig,fsw/Twig,peterkokot/Twig,hhamon/Twig,jamessingizi/Twig,craue/Twig,framewr/Twig,znerol/Twig,framewr/Twig,moltin/Twig,gencer/Twig,Rvanlaak/Twig,derickr/Twig,Tobion/Twig,moufmouf/Twig,moufmouf/Twig,markstory/Twig,bocharsky-bw/Twig,dkarvounaris/Twig,robregonm/Twig,fsw/Twig,huang53798584/Twig,iKwinto/Twig,jamessingizi/Twig,Tobion/Twig,twigphp/Twig,dkarvounaris/Twig,phansys/Twig,jamessingizi/Twig,framewr/Twig,peterkokot/Twig,apishka/templater,nicolas-grekas/Twig,znerol/Twig,gamernetwork/Twig,derickr/Twig,gencer/Twig,hhamon/Twig,gamernetwork/Twig,apishka/templater,markstory/Twig,twigphp/Twig,dkarvounaris/Twig,iKwinto/Twig,hhamon/Twig,Tobion/Twig,nicolas-grekas/Twig,bocharsky-bw/Twig,bocharsky-bw/Twig,nicolas-grekas/Twig,iKwinto/Twig,robregonm/Twig