allow roll strings on IRC to have an 'a' natural language prefix

Signed-off-by: Brian S. Stephan <bss@incorporeal.org>

dice/ircplugin.py

@@ -24,7 +24,7 @@ class Dice(Plugin):
 
     def start(self):
         """Set up the handlers."""
-        self.connection.reactor.add_global_regex_handler(['pubmsg', 'privmsg'], r'^!roll\s+(.*)$',
+        self.connection.reactor.add_global_regex_handler(['pubmsg', 'privmsg'], r'^!roll(\s+a)?\s+(.*)$',
                                                          self.handle_roll, -20)
         self.connection.reactor.add_global_regex_handler(['pubmsg', 'privmsg'], r'^!random\s+(.*)$',
                                                          self.handle_random, -20)
@@ -76,7 +76,7 @@ class Dice(Plugin):
     def handle_roll(self, connection, event, match):
         """Handle the !roll command which covers most common dice stuff."""
         nick = NickMask(event.source).nick
-        dicestr = match.group(1)
+        dicestr = match.group(2)
 
         logger.debug(event.recursing)
         try: