Fix failing test and add issuer test (bug 910938)
Bug 909872 - removes Approve and Reject action for privileged apps for reviewers who shouldn't review them.
image url field for collections (bug 911352)
Remove image assets code (bug 860403)
Merge pull request #1040 from diox/remove_image_assets

Remove image assets code (bug 860403)
Fix collection serializers tests
Accept and return slugs for category/region/carrier in collections API (bug 912279)
Merge pull request #1091 from diox/collections-return-slugs-for-stuff

Accept and return slugs for category/region/carrier in collections API (bug 912279)
Allow filtering on ids and on empty (null) values in Collections (bug 911382)

The empty/null part requires a custom implementation of FilterSet.qs,
because out of the box django-filter doesn't allow this at all.
Merge pull request #1082 from diox/collections-filtering-null

Allow filtering on ids and on empty (null) values in Collections (bug 911382)
Merge pull request #1094 from ngokevin/rqtsoftdel

fix rereview queue from breaking due to soft deleted addons (bug 876819)
don't show those three weird deleted add-ons in theme queue (bug 912644)
point theme queue links to the correct respective queue
return 204 on empty query set for ListModelMixin on comm (bug 912239)
fix rereview queue from breaking due to soft deleted addons (bug 876819)