fix theme images not shown on 2nd invalid theme submit (bug 860279)
Use the app's default_locale for post-review notification mails (bug 848844)

Note: the mails themselves are currently sent with no_translation(),
and the templates don't have have translations anyways. This is just
for the app details such as the name.
Merge pull request #784 from diox/reviewer_notification_translations

Use the app's default_locale for post-review notification mails (bug 848844)
Pass signal to ModelBase's update
Moved over old search test to API
Cleaned up reviewer approve signals (bug 879047)
Added @write to indexing tasks (bug 879047)
Also index to new index upon review (bug 879047)
Added feature profile filtering to featured apps api (bug 875009)
add in a payment and upsell api (bug 878862)
remove until the replacement is ready (bug 878350)
Remove use of .decode() in feature listings (bug 877364)
Test fixes
Better logic for packaged app platform selection (bug 879372)
remove region handling for now (bug 878118)
and remove region form (bug 878118)
and the form save (bug 878118)
fix str formatting in calc_checksum
Fix tests broken by 6aac47c
Bump amo-validator