Implement processing of OAM data

[nicholatian]

The purpose of OAMs—short for Object Attribute Memory—are to provide lots of flexibility/control for manipulating complex 2D ‘objects’ in the viewport. One OAM can contain a collection of images that can be shuffled through by the program, and they can be referenced inside animations defined in a config file. These animations support frame-specific millisecond-exact timings, optional looping, and X/Y offsets for each frame relative to an OAM-global origin. All images are stored as 32-bit PNGs.

Also see: https://gist.github.com/nicholatian/a1a19b96dd7bbd66ec01a91d3e1640cd