Notify 200 OK for INVITE that may arrive after another terminal response, in order to let the application layer handle the said INVITE/CANCEL/200OK moratorium state race condition.
Refactor tests.

Fix a crash while sending a response retransmission in a server transaction, after a network disconnection.

Allow absolute URI in Refer-To header, add a test to check it, and fix _belle_sip_header_address_marshal() to not include angle brackets if not needed for absolute URIs.

Allow absolute URI in Refer-To header, add a test to check it, and fix _belle_sip_header_address_marshal() to not include angle brackets if not needed for absolute URIs.

window compilation failure

Remove "fast-*" variants of SIP URI, which were usefull at the time of antlr parser, but no longer now.

By default belle-sip waits for the first PONG response to ensure that
the server supports the RFC5626. If is not received within the timeout,
it will be assumed thazt RFC5626 is not supported by the server.

Now the user can choose to enable or disable such a sanity check as it
may lead to false negatives if the server is quite slow in sending the
PONG or the timeout is not big enough

Add property [sip]/notify_all_ringings to get multiple 18x responses to be taken into account and notified to the application.
This reverses the principle of favouring the first established early media (183).

Do not queue up multiple retranslission of the same message

Add sip/prefer_ipv6 linphonerc property to request whether to start with ipv6 or ipv4 when doing an outgoing SIP connection.