Proposed patch: cancel channel

[Olaf Titz]

> I've now committed this patch to CURRENT.  If you have a chance to write
> some documentation for how to use this mode, that would be much
> appreciated.

I'll take the chance (hopefully I find time) to make a new release of
c-nocem which officially contains support for the cancel mode (the
code is already in the last release), and then I'll put the needed
documentation into that package.

For the longer run I plan to make a new NoCeM client from the current
c-nocem codebase which only works via cancel mode. This would have
much of c-nocem removed and drastically simplified, since most
batching, and all of the ugly fastcancel program including almost all
of the ugly autoconf script, becomes unnecessary.

Olaf