Map keys 1-4, Q-R, A-F, and Z-V to change tiles

It doesn't actually make any changes yet.
Change tile values on keypress
Show cheat keyboard shortcuts on grid
Add missing ;
Get rid of redundant function
Don't show pre-merge tiles. They overlap, and it looks nasty with transparency.
Bind B key to finding the best score (doesn't do anything yet)
To start finding the best move, create a deep copy of the grid.
Finish it.

Write the extended instructions.
Make it calculate the best move.