Finished bbPress AJAX Loops

+ Added AJAX looping for topics in "Recent Topics" and in single forums.
+ Re-wrote substantial chunks of the AJAX replies functions to use some
tricks I picked up while doing topics.
+ Added shortcode support for [quote] , [img], and [spoiler] tags in
forums and comments.

I'm making BIG progress though this bbPress stuff, and it's really
exciting to see it all come together.