It allows the organizer to choose whether participant are speakers or
listener in a conference.
For scheduled conferences, if a participant is not in the list of
allowed participants, he/she will have its role set to listener (i.e
audio stream will be sendonly from the server side and recvonly on the
client side).

Non scheduled conferences will have the organizer and participants to be
speakers.

The dynamic change of a participant role is not supported yet once the
conference is started but it may be done prior to it by updating the
conference informations

- Remove reason field from LinphoneToneDescription
- Store tones by ID
- choose tone based on the reason when a call ends

Add property to disable deletion of empty chatrooms
Enable compiler option '-Wunused-parameter'
Fixed possible null pointer exception in Java wrapper for Android
Update copyright notice in wrapper files

This saves time to establish the audio stream.
Starting before ICE verified was not a good idea: it will trigger retransmissions, and retransmission interval growing over time makes the handshake slower.
Also, fix an issue where callee sets host candidates as default candidates in SDP, sflrx must be preferred.

- create video stream to send and receive participant minatures
- add support for multiple video stream in SDP
- add label to stream to allow unique link between it and each participant in a conference

Correctly set stream direction in NOTIFY based on information gathered from SDP only
Deny subscription if conference event package is disabled
Clean up of main-db.cpp

Fix multicast support design.

- Stop audio stream when setting new device and Filter don't implement MS_AUDIO_CAPTURE_SET_INTERNAL_ID and MS_AUDIO_PLAYBACK_SET_INTERNAL_ID. This fix allow changing device on Desktop while ringback.
- Add Audio stream stop count for tests.

- Rewrite uwp switch
- Fix winsock redefinition
- Add windows switch on headers
- Add static libs in FindSoci search
- Fix cast error

Rewrite offer answer engine, SAL stream and media descriptions and SDP to media description with C++ 14 constructs

- Add Shared Core logic in shared-core-helpers and constructors in factory
- Add high level functions to get the message or the new chat room from a push notification
- Allow wrappers to use linphone logger
- Add core option to send imdn without being registered
- Improve linphone_core_stop()
- Move the paths functions to the same place for all platforms and add paths for iOS shared file system
- Add shared core tests and modify LinphoneCoreManager to create shared cores

- Move and refactor all tone related code to ToneManager class
- Add tone testing in Single Call and Multi Call test suites

Move license to GPLv3, update version number to 4.3.0.