Tweak test imports

[balloob]

• Tweak all tests to import from our entry point. This better mimics how our consumers consume. Also will make it easier for me to run the tests against a Rollup build 👍
• Add missing exported components to src/index.js
• Replace inline ESLint guidance to use mocha syntax with .eslintrc file at root of test dir
• 13 of the files would register for jsdom-global on their own. I instead opted for a mocha option to auto-register it before each file. This allows us to run any test file individually
• Move mocha options to test/mocha.opts so that one can run NODE_ENV=test mocha and it works 👍

[gthomas-appfolio]

Looks good, thanks man