This lets our spec files be .ts instead of just .js. The typescript files will be checked against the public types. Tests are compiled with babel just in time before running them, emulating the jest experience. TypeScript tests are also linted with eslint.
I converted keyboard.spec.js as the first demo. I'll follow up converting some more more tests.
I enabled vscode autocomplete in our test files. Typechecking had too many errors to enable, but it caught some real bugs that I will fix in a follow up.
This patch contains:
* `test/types.d.ts` - d.ts file for our test runner.
* `test/tsconfig.json` - typescript project for our tests.
* JSDoc header in all specs to mark the describe as a TestSuite
* Drive-by fix of a launcher test that was using `if` instead of `it`
* Some drive-by fixes of unimpactful typos in tests.
