Make Class Library

Need to make the TileSpritesSample project into a class library.

Ideas:
- Classes: World, Tile, AnimatedSprite, Sprite, Camera, Player
- Use TDD in order to build modular, cohesive classes using single responsibility principle.

Game Dev Todo

Tile Engine

- Make display/viewport dimensions an exact multiple of tile size. Test.
- Use displaysize / 3 only when drawing animated sprites - not for world tiles.
- Get tiles to be loaded from a file.
- Add support for movement definition files to define where player can move.

Create Editor

- Create files to be used by TileEngine