Spritesheet Hierarchy

Asgard will have many spritesheets: hundreds, perhaps thousands. Further, spritesheets will be added, removed and modified quite frequently during game development as more graphic artists become involved. We should aim to make spritesheet inclusion as simple as possible.

Here's the proposition:
 1. All spritesheets will be stored in the distro/spritesheets/ directory.
 2. The height and width of each still would be encoded in the filename of the spritesheet. A spritesheet with stills W=59, H=120 would be named 59_120.png.
 3. The path to the spritesheet may be found by the spritesheet's name. For example: Hand-Walking-East would be found at:

     "Hand-Walking-East"
     distro/spritesheets/Hand/Walking/East/59_120.png

     "NotMatch-Standing-East-Breezy"
     distro/spritesheets/NotMatch/Standing/East/Breezy/57_117.png

A model like this would ease the inclusion of rapidly more complex and varied sprite sheets while also eliminating all need for the SpriteSheet table in the database.

Considerations:

 *. Animation would need to be smart enough to compute the number of rows and columns in the spritesheet based only on the Height and Width of the spritesheet, and on the Height and Width of each still.