Make everyone use same random instance
Huge overhaul to sprite handling

- Changed .sprite XML format. Various changes, but the biggest was
adding explicity listing each direction for every animation
- Merged SpriteComponent and AnimationComponent into SpriteComponent
- Updated SpriteData / AnimationData to reflect new sprite format
- Updated content pipeline classes to read/write new SpriteData and
AnimationData classes.
- Updated animation methods to seperate the animation name from the
direction
- Removed layers from SpriteComponent
Additional changes from last check in

Apparently git missed these changes. They belong to d9905b8