Simulator instances still get their scripts included somewhat hackily,
but it's overall much less hacky than before. In particular, the
init code is now an actual constructor, allowing TypeScript to perhaps
validate it one future day.
This is a surprisingly minor refactor considering how many files it
touches, but most of this is only renames.
In terms of file renames:
- `tools.js` is now `sim/dex.js`
- `battle-engine.js` is now `sim/index.js` and its three classes are
in `sim/battle.js`, `sim/side.js`, and `sim/pokemon.js`
- `prng.js` is now `sim/prng.js`
In terms of variable renames:
- `Tools` is now `Dex`
- `BattleEngine` is now `Sim`
- `BattleEngine.Battle` is now `Sim.Battle`
- `BattleEngine.BattleSide` is now `Sim.Side`
- `BattleEngine.BattlePokemon` is now `Sim.Pokemon`