Add missing mdpi, hdpi, xhdpi drawables for new theme engine

Change-Id: I70dd75257f0e3a0a20b844a1ea3cc36506de177b
make LinearColorBar themeable

Move colors to resources and use them instead.

Change-Id: I923e5daa219f302dc24e62faab666483109e6620
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>