This is a quick and dirty little wrapper for the Textile parser.
BBPress's existing HTML cleaners will be de-activated; Textile will be the only markup syntax available.
TO DO: * wire up some admin-panel controls for Textile's options (is this possible yet, in bbpress' current state?) * strip out all but an approved list of URL protocols from the result * make sure turning off the existing input filters hasn't opened the door for any SQL injections * consider storing the parsed HTML instead of the raw Textile; this would mean finding an HTML-to-Textile parser to run before a post is edited. * add a pop-up window with full Textile syntax help