Adds a button to filter contents next to the sort button on grid pages
The filters are saved and restored you return to the page. It works with
#278, playing the filtered items in the sorted order.
The drop down menus for both sorting & filtering are updated to closer
match the overall look.
Filters for:
- Played or unplayed
- Favorite or not
- Genres
- Community (star) rating
- Parental rating
- Video type (HD vs SD, etc)
- Release year and/or decade
