Added sprite animations. Also added comments

Awesome Reimu is awesome.
Added new class called "AnimatedTexture" that can be used to make
animated sprites. Also added a bunch of comments to make code more
readable. Also made a change to the way textures are loaded.  And maybe
a few other things that l forgot, feel free to check the change log and
see what you might want to integrate into your version.
Weird Coding Structure FTW (good luck deciphering it xD comments will
help you)