(cherry picked from commit fa0a7bbb)

Restore -Wunused-parameter compilation warning.

Fix crashes due to incorrect ownership management of some returned objects, introduced in previous commit.

Updated liblinphone to prevent race condition crash when stopping Core while Service is alive on Android

Use JSON to serialize iOS push notification payload.

Change flexisip tester DNS server to fs-test-5.linphone.org

It is activated with LINPHONE_BUILDER_WINDOWS_TOOLS_CHECK If a check has been already done and is successful, it will avoid to update them on each build.

Updated liblinphone to log warning or error if no active/available network found + keep mobile DNS servers at the end of the list if not the default network on Android

Liblinphone: Add a function to create a Content from a file path.

Fix a crash on mkv when stream cannot be duplicate.

    - remove useless rc files
    - clean memory leak in secure message test
    - remove useless usage of fixed filepath for zrtp db

Fix a crash where a csrc change is reported in a video stream but the attached conference no longer exists. Rework a bit.