Semantic-izing the HTML and data output

Right now we have some hodgepodge HTML for layout, so this is an attempt to make it more semantic.

Because of this I've also picked out a another thing all Onebox views have to have: a title. So I've made those oneboxes without a title have a title by changing a value.

This is also one small step towards differing layouts per type.

While most of the changes here are private, I have removed pieces from the subviews. I believe this consitutes a public API change. The release this goes into will have to be a major version bump.

Oh I also fixed some memory issues with the github oneboxes.