Co-Authored-By: Saúl Ibarra Corretgé <s@saghul.net>

Trigger renegotation only when negotiationneeded event is fired on the browser.
Do not disable simulcast for screensharing in unified plan.
Fix the order of the simulcast streams for Firefox

Use unique session id per TPC.
Translate a=rid to Jingle only when simulcast through RIDs, i.e., ssrc-less simulcast is supported

Send conference.join event only after the peer connection is created.
This way we won't send events for lonely calls.

...connection dropped with an error.

Copy/paste mistake - there's no such thing as this.connection in
the XmppConnection. Hard to track down because no error is logged.

...if one is already in-flight.

Either connect or attach can be used to initiate the connection.

Use the rest argument expression to not miss any.

When Jiconop is used to attach to a warmed up BOSH session Strophe goes
to ATTACHED instead of the CONNECTED state.

The LastSuccessTracker has direct access to the Strophe.Connection.

The XMPP stream resumption will enable automatically if supported by
Prosody on Websocket connections. Pass the 'enableWebsocketResume'
config option set to 'false' to disable.

Websocket keep alive is HTTP GET request sent on the service URL passed
to Strophe. It is used to keep the stick tables alive. The feature comes
in enabled by default whenever Websocket are used. Pass
'websocketKeepAlive' config option set to -1 to disable.

See the code for more details about the default interval value.

If Strophe goes to the ERROR state it will pass the error message there
and then transition to the DISCONNECTED state, but without any error
msg.

Given that the XMPP connection is able to reconnect after a drop, now
the jingle session needs to hold off any updates that have to be sent
while the signalling is down. Send the update upon reconnect to sync
Jicofo and JVB with the client's source description.

It makes it easier to remove listeners.

The connected flag is flipped to true as soon as transport connection is
established by Strophe(such as WebSocket TCP), but it doesn't mean that
the connection is ready to send stanzas yet.

All calls to connection.send should go through the wrapper in order to
prevent breaking the connection by calling it in the not connected
state.

This prevents from accessing Strophe internals directly and allows to
block 'send' calls while disconnected. The latter breaks the stream
resume logic by putting stanzas onto the send queue.

TODO make jitsi strophe plugins use the XmppConnection wrapper whenever
possible instead of interacting with the Strophe.Connection directly.

Overconstrainederror occurs when calling gum with "exact"
when on URLs with a hash. To get around this, remove
"exact". Add handling for specified device not being
found, as we can no longer rely on "exact". This
still leaves open the possibility of the wrong
camera being accessed.

Websocket sends queued presence 'unavailable' and the stream close
message correctly when the connection is being closed.

This way it's easier to figure out which parts of the disconnect method are about
cleaning up the connection and the reasons on why it's important can be put in
the JDoc of this method.

There are different types of pings in the app, so it's good to mention
which one is the error being logged for. Also extracts the error
message to give any details about the error.

...it make it easier to process the logs in automated way.

It can either be a websocket or bosh URL, so the current naming is
confusing.