Extends sprite loading class to load sprite sheets.
Extends sprite component to support animations.
Updates the spriteRenderSystem to support animations.
Updates UI rendering to support changes to sprite loading.
Updates demo to support new animation system.
Implements the ability to set the center of a sprite.
Pulls out animation frame index updating from SpriteRenderSystem to AnimationSystem.
Merge branch 'master' into anim
Implements tracking of current animation frame over the network.
Merge pull request #78 from absolom/anim

Implements animation. Closes #6.