Add automatic Drawable mirroring capability when in RTL layout direction

- default value is "no mirroring"
- introduce android:autoMirrored as a new attribute for Drawable,
BitmapDrawable, LayerDrawable, StateListDrawable and NinePatchDrawable
- setting android:autoMirrored="true" means that the drawable will
be mirrored when the layout direction is RTL (right-to-left)
- also fix an issue with ImageView drawable layout direction not
updated correctly when RTL properties were changed

See bug #7034321 Need Drawable RTL support

Change-Id: If595ee5106c786f38e786d3a032e182f784a9d97