implement download using request and jsdom

The download function was originally just throwing errors for
everything, but now it uses request.get to grab HTML and then jsdom to
parse the DOM.

Error handling needs more thought. For now errors are passed as the
first parameter to the callback, and metadata second.

version bump to: 0.0.2
fix the required version of url-parser
Merge branch 'use-request-jsdom' into master