Update for current hare-sdl2 (02e827d 2022-04-26)

Update for integer changes

Add keyboard input

Including rebinding

Allow the player to rotate in two directions

Rotate tetrominoes around their center

Spawn sets of shuffled tetrominoes

Instead of picking the next one randomly every time.

Play background music

Implement wall kicks

Implement game over state

Implement ghost pieces

Implement line clearing

Initial work on line clearing

canmove: fix collision bug above y=0

Check collisions on rotation attempts

Refactor collision detection

update.ha: remove unused import

Fix L tetromino rotations

Add notes.txt

Add secondary colors

Partially implement rotation

Still missing a test to make sure the next state will fit.