sparse merge

[John W. Eaton]

The sparse-merge branch has been merged with the trunk in the Octave
CVS archive.  I'll probably be making a new "unstable" snapshot within
the next week or so.  It would be useful if people who are using
non-x86/GNU/Linux systems could update from CVS and give it a try and
report any problems before the snapshot.

Much of the work to make this happen was done by David Bateman and was
based in part on Andy Adler's original sparse matrix code from
octave-forge.

Thanks!

jwe