[Rd] Catching warning and error output

[Thomas Friedrichsmeier]

> since nobody has pointed me to an existing solution so far, here is a more
> specific suggestion. Attached you will find two patches against R version
> 2.2.0.

Sorry, seems the attachments were stripped (at least they don't show up in the 
archive). Here are links to the two diffs in question:

http://rkward.sourceforge.net/temp/classify_output_patch.diff
http://rkward.sourceforge.net/temp/classify_output_test.diff

Thomas