An almost functional tetris clone.

Current Keys:

   w     Move left
   d     Move right
   w     Rotate
   s     Move down
(space)  Hard drop

The plan is to roll this into a typing tutor where the keys will change with each new tetromino

Written to learn some rust and eventually make it into a typing program. It is using the ggez game engine, but I now believe that engine is probably overkill for what I need here. I'm also pretty sure I'm not using it correctly.