added `element` type

based the check off of [underscore's `isElement`](https://github.com/documentcloud/underscore/blob/master/underscore.js#L931)

couple things to note:
- had to convert to html reporter. tried to stay as similar to the html reporter test code from [component/url](https://github.com/component/url) as possible, but i'm not sure what the `serve .` is in the `Makefile`, so i went for `open`. happy to fix it though
- split the tests into categories, happy to reverse that though
- the test expecting `new String('whoop')` to be `'object'` was failing on master because it was matching `'[object String]'` first, dunno what you wanna do about that, but commented out for now