The print.css link shouldn't be "alternative" but just plain style, since it's enabled only for the "print" media type and we don't want theme zen's or any other js to accidently select it ...
Cleaned up forums.js. As discussed in e-mail, changed generic function names such as "toggle()" to "forums_toggle()" to reduce the odds of future name clashes causing as much confusion and embarrassment as the recent ones in zen and forums did. Made formatting consistent. Got rid of template::head calls to load unused javascript which just made the code more confusing.
Behavior matches .LRN 2.2 behavior, the arrow on a message collapses or expands that message only, not its subtree. Subtree would probably be better (and I swear it did, once upon a time) but that will have to wait for the future if people want it.