This gallery extension has a basic app page that opens when you click on app in list

Change-Id: I2c7b5bc13fbdd83a435294dcf1817a7dadff1f5b
Gallery with comments and modified callbacks

Change-Id: I90b82177bedd4057fc57a7589ac3a8b7a176ddaa
Merged dave's new code of app page and comments
Finished single app page basic, open zip