Always saves password as we can make several room join attempts.

fix(xmpp.js): User id format

Fixes desktop sharing.

Fixes resolving this when passing function after enabling es6.

Fix createConnection broken in 9781a0d

The places of the two arguments of the function createConnection were
switched in the function definition but the call to the function
remained unchanged.

ES6 for modules/xmpp/xmpp.js and it's related files

ES6 for JitsiParticipant

ES2015

ES6 for JitsiTrackError

ES6 for JitsiTrackEvents

Adds a option to set custom callstats script.

Enable ES6/ES2015

Handle session-terminate

Use 'sendToAll' for 'session.restart' and 'session.terminate' events.

Moves analytics event for feedback to the library.

Enable lipsync by default + fixes

Because the flag is required in the connection options anyway it will
be better to use it from one options set only to avoid redundancy.

Not doing so will cause issues when trying to mute after
'session-terminate', because the PeerConnection is closed and should not
be used anymore.

When call ends the PeerConnection is closed and the SSRCs stored in
the local track will not match those assigned the PeerConnection when
it's reopened for new session. This will confuse SSRC replacement logic.
We need to reset those SSRCs and re-register 'ssrcHandler' listener to
get the new ones.

The event is triggered when Jicofo sends 'session-terminate' and our
PeerConnection is closed.