Small video scale refactor

Made the code only do the math once.
Added AnimatedSprite (broken right now)
Fixed typo
Implemented AnimatedSprite more, added to Entity

This had far-reaching implications. Mainly the issue was having to stash
a sf::Texture pointer into AnimationSet. Not the end of the world.
Made AnimationSetCache take AnimationLoader ptr
Made AnimationLoader less static
MAJOR Animation overhaul

Replaced animation mechanism with AnimatedSprite and all affected
classes have been updated. This change should separate some concerns by
keeping most animation stuff in the AnimatedSprite instead of the
object itself.
Merge pull request #104 from zackthehuman/master

MAJOR: Fixed AnimatedSprite bugs and refactored all GameObjects to use it