Merge pull request #191 from nwittstruck/master

Fixed typo - incoming instead of incomming
Don't add the x-goog-conference flag if there are no simulcast senders
Improves simulcast logging.
Remove useless localStream field from NativeSimulcast and NoSimulcast classes.
Modifies a comment.
Fixes desktop sharing when used with simulcast.
Enables the welcome page in config file.
Fixes typo in comment.
Fixes focus addSource/removeSource methods.
Fix the direction string.

Used to return 'sendre' instead of 'sendrecv'.
Fixes simulcast on latest Chrome dev (40.0.2214.5).
Cleans the words list.
Fix converting a format with multiple parameters from Jingle to SDP.
Fix a double variable declaration.
Fixes purging config for jitsi-meet-prosody.
Fixes configuring certs if files already placed in /etc/ssl.
Fixes purge jitsi-meet-prosody (missing debconf configs).