Add support for TURN servers as per the TURN REST API (http://tools.ietf.org/html/draft-uberti-behave-turn-rest-00)
The config is not hierarchical
Use standard base64 encoding with padding to get the same result as
coturn.
rename endpoint to better reflect what it is and allow specifying multiple uris
Oops
Hopefully implement turn in the web client (probably wrong for Firefox because Firefox is a special snowflake)
The REST API spec only alows for returning a single server so name the
endpoint appropriately.
Refresh turn server before the ttl runs out. Support firefox.
Make turn server endpoint return an empty object if no turn servers to
match the normal response. Don't break if the turn_uris option isn't
present.
Add stun server fallback and I-told-you-so message if we get no TURN server and the connection fails.
Merge branch 'turn' into develop