…nkleonrose/mocha into pull/2059

* 'fix-1417-multiple-done-calls' of https://github.com/frankleonrose/mocha:
  Fix #1417: Show actual error, not 'multiple calls to done()'

# Conflicts:
#	test/integration/regression.js

- mostly whitespace changes
- add `'use strict';` everywhere
- fix problems with unused variables, bad variable names, multiple declarations, unreachable code, yoda expressions, error handling, instantiation, etc.
- add a few eslint directives to avoid rules when needed
- switch to YAML eslint configs
- remove `test/` from `.eslintignore`
- add `mocha.js` to `.eslintignore`
- add userland `assert` as dev dependency (as is recommended)
- rename `test/fixture-expect.js` to `test/setup.js`; add global `assert` here
- add `assert` and `run` globals to `test/`'s eslint config
- update `test/mocha.opts` as appropriate
- update `lint` target in `Makefile`
- update eslint environments as appropriate