[ITP, RFU] Unison: new, updated, and obsoleted packages

[Andrew Schulman <schulman.andrew@epamail.epa.gov>]

I have several changes for the Unison packages in Cygwin:

* All of the unison* packages now use a cygport build method.  This is the 
first time I've used cygport with unison*, so someone may want to review 
that part.  It works fine for me.

* New package:  unison2.27.  This is a new package for Cygwin, because it's
an incompatible version with the other unison* packages.  But it's still 
Unison, with the same package layout as all of the other unison* packages.  
So I don't think any package review is needed, except possibly for the 
cygport build script as described above.

* Updated packages: unison2.13, unison2.17.  These have updated README.Cygwin
files and now use a cygport build method.

* Obsoleted packages:  unison2.9.1, unison2.9.20, unison2.10.2, unison2.12.0.
- I looked in Debian, Fedora, openSuSE, and OpenBSD, and none of them are
still using these versions-- all have moved on to 2.13 or later.  
- Upstream source is no longer available for all of them except 2.9.1, and
that version was pretty buggy.
- I asked three days ago on the cygwin list if anyone still needed these
packages and why, and I didn't hear anything to make me think they're still
needed.

Question: what should I do about these obsolete packages?  I could release
new setup.hints for them with category: _obsolete, but would that force users
to uninstall them the next time they updated?  I don't want to maintain those 
packages any more, but I don't want to force users to uninstall them either.

Thanks,
Andrew.

# unison2.27
wget \
  http://home.comcast.net/~andrex/cygwin/unison2.27/setup.hint \
  http://home.comcast.net/~andrex/cygwin/unison2.27/unison2.27-2.27.29-1.tar.bz2 \
  http://home.comcast.net/~andrex/cygwin/unison2.27/unison2.27-2.27.29-1-src.tar.bz2
# unison2.17
wget \
  http://home.comcast.net/~andrex/cygwin/unison2.17/unison2.17-2.17.1-2.tar.bz2 \
  http://home.comcast.net/~andrex/cygwin/unison2.17/unison2.17-2.17.1-2-src.tar.bz2
# unison2.13
wget \
  http://home.comcast.net/~andrex/cygwin/unison2.13/unison2.13-2.13.16-2.tar.bz2 \
  http://home.comcast.net/~andrex/cygwin/unison2.13/unison2.13-2.13.16-2-src.tar.bz2