More changes - not finished
Cleaning up AddonPremium model (bug 895937)
change theme saving tasks to the images celery queue (bug 883272)
Commit from Mozilla Verbatim by user valastiak@mozilla.sk.: 2931 of 5474 strings translated (857 fuzzy).
Merge pull request #1118 from alexmiog/alexmiog_el

[l10n][el] More changes - not finished
Merge pull request #1127 from diox/collections-strip-translations

Strip incoming translations in the API (bug 915656)
upgrade django (bug 916790)
Merge pull request #1128 from davidbgk/895937-cleanup-premium

Cleaning up AddonPremium model (bug 895937)
Avoid calling MakePremiumPerAccess twice (bug 890044)

As weird as it seems, removing that whole part solves the issue because
the price is already updated during the creation process just above
during the `bango_account_list_form.save()` call.
Commit from Mozilla Verbatim by user petercpg@mail.moztw.org.: 5002 of 5474 strings translated (16 fuzzy).
Merge branch 'master' of ssh://github.com/mozilla/zamboni
bump app-validator
update app-validator
Commit from Mozilla Verbatim by user petercpg@mail.moztw.org.: 5038 of 5474 strings translated (0 fuzzy).
Merge branch 'master' of ssh://github.com/mozilla/zamboni
Commit from Mozilla Verbatim by user petercpg@mail.moztw.org.: 5041 of 5474 strings translated (0 fuzzy).
add line breaks between parent css rules and nested for @mattbasta
Merge pull request #1145 from ngokevin/csslinebreaks

add line breaks between parent css rules and nested rulesets for @mattbasta
Updated APIPinningMiddleware to use the cache backend
Fixed tests