Add OSD headerbar and transition to floating mode

src/controls.js

@@ -28,8 +28,6 @@ class ClapperControls extends Gtk.Box
         this.currentPosition = 0;
         this.currentDuration = 0;
         this.isPositionDragging = false;
-
-        this.isMobileMonitor = false;
         this.isMobile = false;
 
         this.showHours = false;