Use SCREEN Xfermode for keyguard badges; update SeekBar

Plumb through the necessary API features through Drawables and
ImageView but leave it hidden for now pending future API review and
plumbing through the rest of the framework Drawable implementations.

Update SeekBar assets used for keyguard transport control.

Set selected status directly instead of finding views by id.

Bug 10531608
Bug 10784913

Change-Id: Ia38bd04ad1bc26e9e6da1dda8a374c9ba3ceccb3