Delays are getting closer.
changed from ij to xy to make reading easier.
minor refactoring for clarity
refill working properly, refactoring

- removed unwanted tile spacing
- renamed GEM_SIZE to TILE_SIZE
- removed OTHER sprites (for now)
- refactored create() to use a move_gem() function
- removed an unneeded param on checkandkillmatchedgems
- lots of comments
- renamed durationMultiplier to distanceMultiplier
- refill board now works properly