Add appcompat-v7 21.0.0.
Add appcompat-v7 21.0.0.

artemnikitin/SeriesGuide,0359xiaodong/SeriesGuide,UweTrottmann/SeriesGuide,UweTrottmann/SeriesGuide,epiphany27/SeriesGuide,r00t-user/SeriesGuide,hoanganhx86/SeriesGuide