Cleaned spammy output to IMC users from IRC and evennia channels, where channel names tended to be added

after one another several times. IMC is not seeing the IRC channel name anymore, output should be on the standard
simple name@MUD: msg format as far as IMC is concerned.
/Griatch

src/imc2/packets.py

@@ -139,7 +139,10 @@ class IMC2Packet(object):
             return '*'
         elif str(self.sender).isdigit():
             return self.sender
-        elif self.sender:
+        elif type(self.sender) in [type(u""),type(str())]:
+            #this is used by e.g. IRC where no user object is present.
+            return self.sender.strip().replace(' ', '_')
+        elif self.sender:            
             # Player object.
             name = self.sender.get_name(fullname=False, show_dbref=False, 
                                         show_flags=False,