Revert "Change ".application" to ".app""
Revert "Change ".application" to ".app""

This reverts commit c0c60be35a4dc26aac06b6adf96360987501d121.

artificechicago/camp2016,wcyuan/weather-mailer,Romzz/appengine-guestbook-python,t9nf/appengine-guestbook-python,ashwini0529/appengine-guestbook-python,dmolson/appengine-guestbook-python,JonGal/appengine-ml-demo,artificechicago/camp2016,adjohnson916/appengine-guestbook-python,thejeshgn/appengine-guestbook-python,jerarl/gcp-appengine-python,GoogleCloudPlatform/appengine-guestbook-python,JackConnor/portfolio,JonGal/appengine-ml-demo,bkeyvani/appengine-guestbook-python,GoogleCloudPlatform/appengine-guestbook-python,jerarl/gcp-appengine-python,Romzz/appengine-guestbook-python,adjohnson916/appengine-guestbook-python,bkeyvani/appengine-guestbook-python,thejeshgn/appengine-guestbook-python,JackConnor/portfolio,jeffgodwyll/appengine-flask-guestbook,wcyuan/weather-mailer,t9nf/appengine-guestbook-python,dmolson/appengine-guestbook-python,ashwini0529/appengine-guestbook-python,jeffgodwyll/appengine-flask-guestbook