Enable the full screen mode

[shamilnabiyev]

Enable the full screen mode for the control buttons and the jointjs paper. Wrap them into a single div container

function enterFullscreen(element) {
  if(element.requestFullscreen) {
    element.requestFullscreen();
  } else if(element.mozRequestFullScreen) {
    element.mozRequestFullScreen();
  } else if(element.msRequestFullscreen) {
    element.msRequestFullscreen();
  } else if(element.webkitRequestFullscreen) {
    element.webkitRequestFullscreen();
  }
}

enterFullscreen(document.documentElement);               // the whole page
enterFullscreen(document.getElementById("ControllersAndPaper")); // an element