Bump version number, and revert JSON API version bump

There's no need to bump the JSON API version number at the moment. We don't use any of the new features yet and bumping the version number requires us to release two different versions one for gotham and one for helix.
Show placeholder artwork if no poster/fanart available for a movie
Merge branch 'fixes/no-artwork'
Add button to clear genre filter
Add button to clear selected genres
Merge branch 'fixes/clear-genre'