NOTE: SIP over TCP is disabled for now on Windows, waiting for
TLS 1.3 support. To re-enable it, check the #ifdef _WIN32 in
ice_transport.cpp

Our pjsip version supports the RFC6544. With this patch, when
starting a call, the daemon is using two ICE sessions for the SIP
channel. One is negotiating a UDP socket, and the other a TCP socket
and transmits both SDP on the DHT.

If both negotiations succeed, TCP is prefered and will be used
to transmit SIP messages and the VCard. This should solve the 30
seconds timeout on bad networks.

Note that the media channel is still using UDP to transmit audio
and video.

MAJOR CHANGE: the SIP channel use TLS on top of TCP, no DTLS,
so the transport is considered as reliable.

Also lot of changes in rfc6544.patch to link to rfc6062. The patch
needs to be cleaned, cf TODO notes

Also this seems to fix the ICE shutdown at the end of the call
(after the IDLE Timeout)

Change-Id: I01210da3abfcc448071268b4e1e38abdd58f9f05
Gitlab: #103
Gitlab: #108