work = function() {
	      setTimeout(function() {
	        if (!NProgress.status) return;
	        NProgress.trickle();
	        work();
	      }, Settings.trickleSpeed);
	    }
Hides the progress bar.
This is the *sort of* the same as setting the status to 100%, with the
difference being `done()` makes some placebo effect of some realistic motion.

    NProgress.done();

If `true` is passed, it will show the progress bar even if its hidden.

    NProgress.done(true);