Add option to use the Android hardware scaler by setting a low resolution

http://android-developers.blogspot.se/2013/09/using-hardware-scaler-for-performance.html

Uses this feature I added to native: https://github.com/hrydgard/native/commit/1012f46dee3473376eff2a549c64a7f2356461b0

This should help high-resolution devices a bit, like those zany 2560x1440 phones.

I can't figure out a good way to describe the option in the UI though...