Started implementing the large canvas
Merge branch 'dev' of https://github.com/math1man/SuperMacalester into dev
The large canvas works.  All non-building (except plain asphalt) tiles have been implemented via the large canvas.
The character canvas also works.
All unused sprites in the above two sets have been moved to subdirectories labeled "unused"
Additional makeSprite and split methods have been added to SpriteUtils
SpriteUtils now deals entirely in grid units rather than pixel units.  The conversion factor is defined by Grid.GRID_PIXEL_DIMENSION
Tiles now store their tileKey for future debugging purposes