v16.3 update notes

This is just a minor version update; pushing it out so I can start getting v17 into beta.

• &rooms=room1,room2 has been added for easier multi room transfer (via duncan)
• &website embedding has been greatly improved; twitch/youtube support streamlined.
• guests will get a message when transferred
• &scenes can be used by the director to allow for more scene buttons (&scene=3 for example can be used now) ( &scene=2 is funky, so keep that in mind if using it )
• &showchannels is added to the director's options; it lets you output audio of a guest to a different audio channel>
• improve mobile support; rotating the phone doesn't break the sizing of videos (bug in v16 fixed)
• &vd and &ad now support device names and still device sink IDs.
• changed the fullscreen icons
• languages updated (dutch)
• numerous other polish items added, including some fixes contributed via github by users.

Thank you to everyone for the feedback and suggestions. -steve