Hightlight Tracking Update

[MICHAEL MCDONALD]

I removed the 'screen compare' mode from speakup, so now there is only
the new 'highlight tracking' mode.  I also cleaned up the code I was
working on a bit.

I've also added code to set the reading cursor to the position of the
highlight, but there are problems with it.  It is being reset by
speakup_con_udpate function, so I will probably have to disable that for
highlight tracking mode.

Michael