Fixing stats tests
L10N update for Czech (cs)
Merge pull request #980 from JasnaPaka/master

L10N update for Czech (cs)
fix rereview themes images getting deleted from mv'ing two same filenames (bug 876819)
fix app dropdown menus showing from theme queue
fix theme log returning app results (bug 871736)
check for token validity before saving note from email
fix pending theme queue for themes that also have rereviews
fix squished theme hovercards on the homepage (bug 881391)
typoes to the css rule from the last patch
Add region/category/carrier filtering on Collections (bug 903489)

Also, implement dynamic filters fallback : if the current set of
filters don't return results, remove one and try again till we have
exausted available filters or we have found some results.

django-filter 0.7 upgrade is necessary to fix a bug regarding filtering
on '0' values.