Tweaked the rectangle-rotating function to not have subtle, 1-pixel rounding errors when objects are rotated by multiples of 90°.
Removed the ancient colorshift_hash_table code because it was never used and never worked.
Merge branch 'master' of https://github.com/anura-engine/anura

Conflicts:
	MacOS/Frogatto.xcodeproj/project.pbxproj - discarded