... by moving code to stream.c. Thanks to the new design, new cases are
not really needed, resulting in cleaner code.

I also did a cleanup of header file usage as a side-activity.

pkg-config uses uppercase for its _CFLAGS and _LIBS variable names.
So we follow suit and convert all _cflags and _libs variables to
uppercase for more consistency.

The limit can now be set via $MaxMessageSize global config
directive (finally gotten rid of MAXLINE ;))

Also added redirector to web description of error codes
closes bug http://bugzilla.adiscon.com/show_bug.cgi?id=20

Signed-off-by: Rainer Gerhards <rgerhards@adiscon.com>

reduced dependencies, moved non-runtime files to its own directory except
for some whom's status is unclear

GNU/Hurd does not define it (because it has no limit), and we have taken
care for cases where it is undefined now. However, some very few places
remain where IMHO it currently is not worth fixing the code. If it is
not defined, we have used a generous value of 1K, which is above IETF
RFC's on hostname length at all. The memory consumption is no issue, as
there are only a handful of this buffers allocated *per run* -- that's
also the main reason why we consider it not worth to be fixed any further.