Fix Mosaic layout refreshing.
Add missing header of avatar.
Fix hidden header in chats by using a var instead of qvariant coming from model (seems to be unconsistant as $chatEntry could be defined as undefined while having still its value).
- Move active speaker managment to list instead of proxy (to be next to the new API state changes).
- Update participants on conference created event to avoid losing me and other devices (SDK callbakcs are not usable before create event).
- Fix selected active speaker when being in conference without participants.
- Fix active speaker on new/left participants.
- Protect mosaic transitions from deletion.
- Username selection from IncallAvatar.
- Deletion protection on camera when changing layouts by introducing a minor delay.
- Shutdown preview when going out from waiting room.
- Update design of waiting room.
- Change flipping transition to opacity.
- Update SDK (fix the camera reset of Active speaker when new participant)
- Fix blanks lines in chat menu.
