Bug 1042960 - Create UI elements for facet bar

This is a WIP that addresses two challenges with the design for bug 1042960.

1) One-sided borders are tough. They require hacky layer lists or a 9 patch, which is doable, except:
2) How would we change their colors based on the search engine? 
You could dynamically add these in PostSearchFragment.onCreateView. You could get a SearchEngine instance in there and use that to determine which facets to add. Although as a first step you could just hard-code what facets you're adding until we add facet support to SearchEngine.