Fixed bug in atlas packer which created missized nodes.

The "fits exactly" check was passing if *either* width or height
matched, not both.
Added sprite db csv reader.
Split background stars atlas.
Refactor SpriteDb sequence lookup.
Added spritesheet reading to atlas packer.
Moved sprite db out of RenderState
Fixed off-by-1 rect sizes in atlas packer.
Fixed spritesheet slicing in the atlas packer.
Split ships.png texture.