Investigate how we can indicate that a menu is open/closed to voiceover
Background
These elements of the page are currently somewhat confusing. If you manage to open a menu, voiceover still thinks you are at the same spot in the document, instead of moving you into the menu. I found an implementation and explanation that might be useful to fix this.
1: http://marcysutton.com/page-scrolling-in-mobile-safari-voiceover/
2: https://a11ywins.tumblr.com/post/116427997643/voiceover-accessible-slide-menu
3: http://codepen.io/marcysutton/pen/JoQqVw
P.S. These should probably be oojs UI elements, so that they can be reused properly.