Graphics rotation

Rotation algorithm that uses matrix shearing. https://www.ocf.berkeley.edu/~fricke/projects/israel/paeth/rotation_by_shearing.html It can rotate the graphics page by any arbitrary angle, but you're limited on how large a rectangle you can rotate without losing some corners because they're cut off by the GRP's 512x512 boundary. 400x400 was the biggest I've tested, but I don't feel like doing the math to figure out the actual largest size. It's the 100% fastest dang thing possible.

Instructions:

Instructions for using the DEF blocks in the code.