Level refactor to support level sets
Register all level sets
Add level set menu option
Move some copy
Remove LEVEL_DIFFICULTY references, replace with LEVEL_SET
Fix annotations and references
Refactor levels, start
Move levels
Inversion of control in snake moving and collisions
Get basic level functionality working again on client
Move snake controls to separate object
Move some shape painting logic to ShapeGenerator
Apply gravity to level
Uppercase menus
Make level animations work again
Set up scrolling cave level
Delay registering animations to prevent xss.shapegen undefined error
Fix collision detection in shifted animated objectso
Fix menu snake
Global level cache