add dd ``python -m gunicorn.app.wsgiapp``` support
add dd ``python -m gunicorn.app.wsgiapp``` support

fix #493

1stvamp/gunicorn,gtrdotmcs/gunicorn,zhoucen/gunicorn,jamesblunt/gunicorn,ccl0326/gunicorn,keakon/gunicorn,ammaraskar/gunicorn,gtrdotmcs/gunicorn,elelianghh/gunicorn,zhoucen/gunicorn,1stvamp/gunicorn,gtrdotmcs/gunicorn,wong2/gunicorn,jamesblunt/gunicorn,prezi/gunicorn,prezi/gunicorn,alex/gunicorn,malept/gunicorn,tempbottle/gunicorn,ccl0326/gunicorn,ccl0326/gunicorn,zhoucen/gunicorn,wong2/gunicorn,1stvamp/gunicorn,prezi/gunicorn,alex/gunicorn,malept/gunicorn,wong2/gunicorn,WSDC-NITWarangal/gunicorn,harrisonfeng/gunicorn,jamesblunt/gunicorn,ephes/gunicorn,GitHublong/gunicorn,tejasmanohar/gunicorn,z-fork/gunicorn,mvaled/gunicorn,MrKiven/gunicorn,mvaled/gunicorn,malept/gunicorn,alex/gunicorn,mvaled/gunicorn,beni55/gunicorn