Build: Don't assume the browser environment; smoke test on Node w/ jsdom

Refs gh-1788
I don't like it either. :) But it seemed as a necessary evil.

We don't know if something in the ajax folder isn't run immediately when including jQuery. We know this about `parseXML` and the `xhr` transport but this seems dangerous to do globally for ajax.

I'm open for better suggestions; I just don't see them currently.