Identify current location for notes and citations

Screen readers many times use a virtual buffer. This is different from the visual presentation of the information. It is critical to know exactly where you are on a page. We need to identify the best ways to do this for leaving notes in margins, for placing bookmarks, and for citations and generating references.

One approach is to highlight some text and copy it to the clipboard. The flaw with this approach is that it might not be unique. Other approaches involving using a mouse click at the proper location. These approaches need to be researched to come up with a recommendation.

This relates to issues 55, 85, and 86.