Add documents link to header on doc difference

Problem
Using the Document difference feature, when the user changes the document on one of the drop lists, one new browser history item is added.
This results that the user, as to click back the same number of times as the times on of the comparing documents was changed.
Mainly in version comparison, users want to go back to the document and try to use the browser back action.
Also, someone given a comparison link may want to navigate to one of the compared documents.

Proposed solution
Add the documents title with link on the header