update documentation about styled console logs
update documentation about styled console logs

Firefox now support styled console logs since version 31 (actually on aurora) : https://hacks.mozilla.org/2014/05/editable-box-model-multiple-selection-sublime-text-keys-much-more-firefox-developer-tools-episode-31/
elliottsj/debug,jabaz/debug,elliottsj/debug,CantemoInternal/debug,zacronos/debug,jabaz/debug,visionmedia/debug,CantemoInternal/debug,zacronos/debug