Fix #214
Merge pull request #216 from Ansa89/italian-translation

Italian translation: update
Fix #211
Switch self cam view to OpenCV
Switch network camera to OpenCV
Color compatibility with uTox
Remove all Qt video code
Update Mac build config
Fix #213
Fix #219, handle av media changes

Can now start or stop video on demand of the peer
Always unmute mic when a call ends

Since the mute mic button will be disabled
Use a global AL context, not per-call
Clean & remove old code and dependencies

We don't use QtMultimedia and OpenCV_imgproc anymore

Fixes #218