This patch adds a new configuration option to the URL_Title module so that
the bot configuration may declare a list of regular expressions to match on a
URL in order to determine if it is blacklisted.

This should hopefully address some intermittent blank/simple/default looking
pages returned by YouTube intermittently.

This commit adds a plugin for replacing arbitrary regexes with corrections.
This is similar to the Titillate module, except that only the first match is
replaced, and the whole line with the correction made is returned. This can
be used for common spelling mistakes, or for memey replacements. Since it
is likely to get annoying, there is also a config option to reduce the bot
to only respond with some level of random chance.