Bug fix for issue #66, no chatbot output

1.) Finally found and fixed the problem where a chatbot sometimes
generates a blank output if no AIML categories are found.
2.) Cleaned up some more orphaned debugging code
3.) Added getbots.php to the project, which returns a JSON encoded array
of ID/name pairs for all active chatbots, enabling botmasters to build
selectboxes or radio button groups of chatbots. No more hard-coding bot
IDs or bot names! there is a new example GUI in the jQuery folder
(multibot_gui_with_chatlog.php) that can be used to learn how to
implement this wih a selectbox in an AJAX driven chatbot interface page.