TextTransform: add a !lower

how i got so far without adding this i'll never know

modules/TextTransform.py

@@ -42,6 +42,8 @@ class TextTransform(Module):
             return self.reply(connection, event, reply[0])
         elif self.upper(what, reply):
             return self.reply(connection, event, reply[0])
+        elif self.lower(what, reply):
+            return self.reply(connection, event, reply[0])
         elif self.al_bhed(what, reply):
             return self.reply(connection, event, reply[0])
 
@@ -84,6 +86,17 @@ class TextTransform(Module):
             reply[0] = text.upper()
             return True
 
+    def lower(self, what, reply):
+        """
+        Convert a string to lowercase.
+        """
+
+        match = re.search('^!lower\s+(.*)$', what)
+        if match:
+            text = match.group(1)
+            reply[0] = text.lower()
+            return True
+
     def al_bhed(self, what, reply):
         """
         Convert a string to al bhed.