Merge branch '150-realize-fullscreen-with-html-api' into 'master'

Added fullscreen to toggle button

Closes #150

See merge request arsnova/frag.jetzt!148

src/app/models/rescale.ts

@@ -70,12 +70,14 @@ export class Rescale {
     switch (this.state) {
       case 0:
         this.reset();
+        document.exitFullscreen();
         break;
       case 1:
         this.activate();
         break;
       case 2:
         this.activateFull();
+        document.body.requestFullscreen();
         break;
       default: break;
     }