add_video() no longer exists and is replaced by request_video(), since this function doesn't guarantee video to be established depending on receiver's policy.
Also, it no longer modifies the video policy, for clarity. Instead, it uses linphone_core_accept_call_update() to accept video despite of video policy.

- better integration with network reachability callback
- fix crashes (mTunnelClient can no longer be NULL)
- avoid useless operations during transcient states
- clarify source code
- allow the application to set root_ca before the tunnel connection actually starts.

The same LinphoneTunnelConfig object was
added twice with different parameters

Add possibility to assiocate tags with tests and to run the only the tests corresponding with a specific tag with the --tag option.

proxy config: modify linphone_proxy_config_get_contact and add linphone_proxy_config_get_identity_address returning LinphoneAddress and move all documentation to linphone_proxy_config.h

tester: do not execute TLS tests when it is not available, and avoid using TLS when it is not necessary

Fix a bug in ICE where the session state was not correct when a peer added a video stream during a call and the other peer refused it.

add new test that check that big messages (ICE+ video + lots of codecs) are now passing through the tunnel

fix the tunnel tests, that were not working correctly.

* The tunnel manager are now thre mode : disable, enable and auto
* Two new functions: linphone_tunnel_set_mode() and linphone_tunnel_get_mode()
* linphone_tunnel_enable(), linphone_tunnel_enabled(), linphone_tunnel_auto_detect()
and linphone_tunnel_auto_detect_enabled() are now deprecated.