- The bridge should now support XEP-0115 Entity Capabilities, which actually
brings us into compliance with XEP-0085 Chat State Notifications (there were
clients, like Miranda NG, that wouldn't send to us without us actually doing
this XEP and advertising support in disco#info).
- We now handle the :disconnect message from whatscl, which lets us properly
deal with the connection being removed from the app or replaced with another
session. (Before, this would drop the connection, it'd loop and retry, and
then hit a status code error on login; this way is slightly cleaner and also
prevents the bridge getting into a war with another bridge.)
- The :ws-open whatscl event never existed. The bridge was doing just fine
not executing its handler, so it's just been removed. Future work might
improve the amount of spam sent to the user about the bridge state.
