Added deprecation warning for classic namespaces.
Added deprecation warning for classic namespaces.

envato/rake,ruby/rake,esasse/rake,mat/rake,Vanzct/rake,ruby/rake,codedogfish/rake,taiganakagawa/rake,hsbt/rake,ipmobiletech/rake,zzak/rake,askl56/rake,pjump/rake,bentley/rake,mat/rake,jaustinhughey/rake,hsbt/rake,envato/rake,tmornini/rake,88rabbit/rake,utilum/rake