[Rd] Catching warning and error output

[Thomas Friedrichsmeier]

> What I would like to have:
> Of course there would be many different ways to accomplish this. Here are
> some solutions I can think of:

I just had an additional idea:
4) Export inError, and inWarning from errors.c:
I'm not entirely sure this would really work as expected, but if it did, it 
would be fairly neat. I would receive all output though R_WriteConsole. There 
(in my implementation of the callback), I'd check for "int inError", and "int 
inWarning", and classify the output accordingly. Just as in solution 1), I 
still could not figure out about a direct call of REprintf. Such output would 
still be classified as "regular".

Regards
Thomas