Convert stuff to TypeScript

[dtinth]

Changelog

Several core objects have been converted to TypeScript to make the game code easier to maintain. This includes Judgments, Game, Player, GameInput, GameState, PlayerState and PlayerStats in the game, and Callbacks, Observable and Progress in the utilities.

[codecov-io]

Codecov Report

Merging #544 into master will decrease coverage by 0.37%.
The diff coverage is 94.37%.

@@            Coverage Diff             @@
##           master     #544      +/-   ##
==========================================
- Coverage   81.31%   80.93%   -0.38%     
==========================================
  Files         156      156              
  Lines        4682     4706      +24     
  Branches       77      162      +85     
==========================================
+ Hits         3807     3809       +2     
- Misses        853      857       +4     
- Partials       22       40      +18

Impacted Files	Coverage Δ
src/progress/index.ts	100% <100%> (ø)
src/game/input/control.ts	100% <100%> (ø)
src/utils/observable.ts	100% <100%> (ø)
src/game/input/index.ts	82.35% <100%> (ø)
src/game/player.ts	100% <100%> (ø)
src/game/judgments.ts	96.49% <100%> (ø)
src/game/state/player-state.spec.js	100% <100%> (ø)	⬆️
src/utils/callbacks.ts	76.92% <76.92%> (ø)
src/game/state/player-state.ts	83.76% <90.74%> (ø)
src/game/state/player-stats.ts	91.78% <94.11%> (ø)
... and 8 more

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