Font bitmaps are loaded into memory multiple times

It seems that the bitmap images in font providers are loaded into memory every time, even if they've already been loaded for a different provider / font.

This can lead to OutOfMemoryErrors when creating multiple vertically moved fonts. (I know that this isn't an intended feature in the first place, but I think some sort of cache for these bitmaps would still be a good idea.)

BitmapProvider#create