Fix #2018814: System cannot correctly render assets with "wrap_content" attribute in QVGA

It turns out we were not returning the density for anything retrieved from a
TypedArray...  which basically means any bitmap references from a layout or style...!!!

This is now fixed.

Also fiddle with the density compatibility mode to turn on smoothing in certain situations,
helping the look of things when they need to scale and we couldn't do the scaling at
load time.