Add cursor highlighting for other users editing file

[GoogleCodeExporter]

We did some work with this during builds, but of course didn't get it 
implemented in time.

Here's an example, I believe, of an Eclipse plug-in that does this through 
Annotations:

http://code.google.com/p/chronomancer/source/browse/trunk/chronomancer/src/org/o
callahan/chronomancer/views/SourceAnnotator.java

There's also the idea of using Markers to show where cursor positions are:

http://www.dolejsky.com/2007/12/27/tips-on-developing-eclipse-plugins-ii/

Selection listeners:

http://wiki.eclipse.org/FAQ_How_do_I_make_a_view_respond_to_selection_changes_in
_another_view%3F

FEUs for both cursors and selections should already be handled by the server.

Original issue reported on code.google.com by [email protected] on 1 May 2011 at 4:45