128 was just a bit too much for quadratic algorithms and 8 is pretty
pointless.

This effectively undoes 7cdc05f, which
was honestly a dumb idea to begin with, and turned out to break
exports for some reason after doing a git bisect.

A huge redesign with more features!

[ADDED]
- Optional sound effects based on the average value of compared elements
- Customizable data types (random, reversed, sorted, etc.)
- Big preview mode in level select screen
- Extended, rewritten descriptions of all levels with pseudocode

[REMOVED]
- Tier system
- Sizes of 8, 128, and 256

The previous commits neglected to provide a way for a touchscreen player
to quit a level.

Also swap quicksort controls to match bubble sort.

This update makes the game fully playable without a keyboard!

[ADDED]
- Fully playable with only mouse or finger
- Fully navigable with arrow keys

[REMOVED]
- Most keyboard shortcuts, as they were undiscoverable

[CHANGED]
- Swapped controls for quicksort to match bubble sort

[FIXED]
- Crash on cocktail shaker sort with reversed data

This commit remembers the difficulty of the level just finished and
selects that one after returning to the level screen instead of
hard-coding easy mode.