Imminent Refactor

Thanks everyone who's been reporting issues and contributing changes. The prior form of the code of the parser wasn't terribly readable (I was more focused on getting a MVP out). I've decided to rewrite it for a few reasons:

• To avoid using html5ever because the underlying logic for selectors and transversal was removed from that project,
• To better document how an Microformat item is built (getting its ID, root classes, properties - implied or explicit and its value)
• To allow for a cleaner path to supporting more specialized formats for parsing (like metaformats) and for rendering (like for the smaller JF2, used in things like Microsub and closer to things like JSON Feed).
• To make it easier to pass each of the test cases of https://github.com/microformats/tests

What I'm hoping to have done with the close of this issue is the closure of the above.