Consistent coding style

[alexrudd2]

npm run lint and npm run format should produce a consisent result.

[jedahan]

I'm waiting for all the functional PRs to be merged or closed before submitting a format PR.

[jedahan]

I started a branch ts-standard that

• adopts ts-standard as a zero-config linter and formatter
• sets the tsconfig to strict: true
• adds a git pre-push hook that runs npm test && npm run lint
• sets the local repository hooks directory to githooks after any npm run build

I am slowly working my way through all the issues, which mostly are explicit return types, a dozen or so cases of not handling nulls/undefineds, a few removals of any types, etc.