directed data logger with coloured output

["Thomas Höhenleitner" <thomas at seerose dot net>]

Hello,

because I will have no time for this in the near future and it is already
in a usuable state, I decided to contribute it now, even it is not yet
finished and fully tested.

It is nearly the same thing I placed here in summer, but it is totally
rewritten and now an eCos package.

It's principle mechanism is not far away from the CYG_TRACE code but it has
some options, like channelled output into files or windows and color for
the console. Also it needs less space for the log buffer. May be it makes
sense to merge both packages.

By using variadic macros it was possible to reduce the number of log
macros. This requires a not too old compiler. The argument count must be
still calculated by hand during the coding. I found so far no way to avoid
that, without wasting log buffer space.

The files are renamed from log* into dlog* now to avoid confusion with the
logarithm functions. 

I will be back in the office in January and I hope to get some feedback
then.

Wish you all a nice time.
 
Thomas