Consistently use start/end instead of left/right layout properties.

Fixes various RTL language bugs.

Change-Id: I3be9c9c54e4fd14a561f6b38ce1601bc66c8351b
Add missing mdpi, hdpi, xhdpi drawables for new theme engine

Change-Id: I70dd75257f0e3a0a20b844a1ea3cc36506de177b