[racket] drracket log pane quirks

A few quirks with the DrRacket log pane (as seen with 5.3.1 and other 
recent releases, on GNU/Linux):

* Log pane seems to automatically scroll vertically on new output.  This 
is a problem if user is working through information in the log pane and 
doesn't want to lose their position, or is visually referring to some 
text in the log pane while working in Definitions or Interactions pane.  
(This happens very frequently, when Log pane is on the All or "debug" 
tabs, since GC messages keep losing one's place.)

* Log pane seems to automatically scroll horizontally on long lines.  
Starts of lines, as well of starts of neighboring lines in context, are 
generally more important.  Needs to either stay at the same horizontal 
scroll position, or reset to leftmost scroll position.

* Text in the log pane is different size and typeface than that in the 
Definitions and Interactions panes.  In my setup, this means that I 
can't see as much info at once as I should be able to in the log pane.  
Screenshot: http://postimage.org/image/4worjbfqd/

I've noticed these for a while, but I've been changing some of my tools 
to work better with DrRacket than Emacs, so I'm feeling the pain more often.

Thanks,
Neil V.