* Lint arrow-body-style
* Lint prefer-object-spread
Object spread is faster _and_ more readable.
This also fixes a few unnecessary object clones.
* Enable no-parameter-properties
This isn't currently used, but this makes clear that it shouldn't be.
* Refactor more Promises to async/await
* Remove unnecessary code from getDataMoveHTML etc
* Lint prefer-string-starts-ends-with
* Stop using no-undef
According to the typescript-eslint FAQ, this is redundant with
TypeScript, and they're not wrong. This will save us from needing to
specify globals in two different places which will be nice.
Global types are defined differently for `.ts` files than for `.js`
files, leading to some confusion for past refactors.
This commit defines them correctly.
I'm also considering making certain global types only available under
namespaces, but I don't want to do that to `User` or `Room`, so for
now, there are no changes there, besides putting streams in the
`Streams` namespace (so `WriteStream` is now `Streams.WriteStream`).
