Use the new text_type API, and remove client-side Markdown escaping.
This makes use of the new ?force-text-type capabilities of the API to

force all requests to come in as Markdown. It also ensures all

appropriate text rendered in the templates are Markdown, meaning that

the JavaScript doesn't have to deal with handling escaping. That greatly

simplifies the Markdown-related logic, removes inconsistencies in

escaping logic, and prevents browser-related issues with Regular

Expressions.

Viewed old comments, created new comments, and edited comments for

diffs and file attachments, and for review bodies. Didn't see any

problems (though more real-world testing will be needed).