updateVisibility() {

		if( this.Reveal.getConfig().showNotes &&
			this.hasNotes() &&
			!this.Reveal.isScrollView() &&
			!this.Reveal.isPrintView()
		) {
			this.Reveal.getRevealElement().classList.add( 'show-notes' );
		}
		else {
			this.Reveal.getRevealElement().classList.remove( 'show-notes' );
		}

	}
Updates the visibility of the speaker notes sidebar that
is used to share annotated slides. The notes sidebar is
only visible if showNotes is true and there are notes on
one or more slides in the deck.