plugin calls: update UI: - there is now a "search" UI to select a contact to call - "call" UI is displayed only when we actually are in a call - new control button to (un)mute audio and video - new control button to go to fullscreen/back to normal - add an extra "hang up" button directly in the call UI, so there is always one even in fullscreen mode - UI is similar to the one implemented in web frontend - notification + ringtone + desktop notification on incoming call - if an incoming call is cancelled from initiator, confirmation dialog is removed rel 425