Process postback for anon. purchase (bug 1019269)

This supports server-less in-app payments.
Merge pull request #2115 from kumar303/fxpay-postback

Process postback for anonymous purchase
rename image to background_image for feedapp (feed)
clean up stale custom sql
Pull in elasticutils with django to pick up settings
Removed flush_urls and hera package
Removed urls/views/templates of apps/applications (bug 1008734)