Update FIXME about FF re-connect issue

mumble-client now properly disconnects, so this is no longer an immediate issue
(hence downgrade to TODO).

The protobuf FIXME was resolved with the switch to `mumble-protocol`.

src/main.rs

@@ -1,6 +1,7 @@
 #![feature(try_from)]
-// FIXME don't just unwrap protobuf results
-// FIXME for some reason, reconnecting without reloading the page fails DTLS handshake (FF)
+// TODO For some reason, reconnecting without reloading the page and without disconnecting the
+//      previous connection (i.e. multiple simultaneous connections) causes FF to reject our DTLS
+//      cert. Works in Chrome, or in different tabs or when properly closing the old connection.
 extern crate argparse;
 extern crate byteorder;
 extern crate bytes;