Create thread views

[pbrisbin]

My thought is that we'll have normal pages visible at /comments?thread=x&section=y which can be pulled onto consumer pages via jQuery.load(). A few things need to happen:

• Update getCommentsR to return either JSON or HTML depending on Accepts (this is built into the framework)
• Make an embeddedLayout (or something) which foregoes the usual html and head tags of defaultLayout.
• Add the required templates etc

[pbrisbin]

We'll just build the frontend entirely in JS, and circle back to server-side templates later.