SizeConfigStrategy
Keys Bitmaps using both getAllocationByteCount and the android.graphics.Bitmap.Config returned from getConfig.
Using both the config and the byte size allows us to safely re-use a greater variety of Bitmaps, which increases the hit rate of the pool and therefore the performance of applications. This class works around #301 by only allowing re-use of Bitmaps with a matching number of bytes per pixel.