_return_tweet_or_retweet_text used to both determine the proper tweet
text and bot.reply() with it to the provided event. if we're not
reacting to an irc event, this obviously won't work, so this pulls the
method into two things so that we can use the string formatting code
without necessary needing an event
get rid of is_admin(), instead check for django permissions. a couple
things were using is_admin(), so now there's an example of the
permission adding and usage, as those were ported
Brian S. Stephan