Make all the markdowns the same

Currently we have 3 different markdown or markdown-like implementation, and the only one that consistently works is the 'more info' implementation.

We need to move all implementations to that one. Key features to add are:

1. Allowing a 'open in new window' option for links
2. Ensuring that normal markdown features work and look good
3. Ensuring that inserted images are appropriately sized (not bloated if large) to the screen.