module meta option to ignore when bot is addressed directly.

the motivation for this is if you have commands that have been aliased
that you do not want to fire when they normally would via 'bot: blah'

Module.py

@@ -108,8 +108,16 @@ class Module(object):
         except NoOptionError: pass
         except NoSectionError: pass
 
+        ignore_prefix = False
+        try:
+            ignore_prefix = self.config.getboolean(self.__class__.__name__, 'meta.pubmsg_ignore_bot_prefix')
+        except NoOptionError: pass
+        except NoSectionError: pass
+
         if not addressed_re.match(what) and need_prefix:
             return
+        elif addressed_re.match(what) and ignore_prefix:
+            return
         else:
             what = addressed_re.sub('', what)