Add a whois command to the XMPP parser.

parser_xmpp/src/com/dmdirc/addons/parser_xmpp/XmppParser.java

         throw new UnsupportedOperationException("Not supported yet.");
     }
 
+    @Override
+    public void sendWhois(final String nickname) {
+        // TODO: Implement this
+    }
+
     @Override
     public String getLastLine() {
         return "TODO: Implement me";