Upgrade procedure for tetex

[Christoph Martin <martin@uni-mainz.de>]

This is the upgrade procedure for tetex.

There is a serious problem/bug in dpkg that prevents the correct
removal of the old tex packages and then the installation of tetex.

dpkg can't handle multiple packages which are to be replaced.

So, do the following:

- Purge all the old tex packages which are replaced by tetex. (E.g. go
into dselect, select the tetex-packages, look which old tex packages
are marked to be removed, purge the packages.)

tetex replaces: amslatex, amstex, babel, bibtex, dvipsk, kpathsea,
kpathsea-dev, latex, latex2e-doc, ltxmisc, ltxtool, makeindex,
mfbasfnt, mfdcfnt, mflib, mfnfss, ps2pk, psnfss, texbin, texi2html,
texinfo, texlib, texpsfnt, textmf, xdvik 

- Purge latex before you purge mflib, because the postrm script of
latex depends on install-fmt-base, which is in mflib, but latex does
not depend on mflib. This is a bug in the old latex package.

- Watch out that all config-files in /etc/texmf/ are removed, at
least texmf.cnf is incompatible. (dpkg --purge should do this for
you.)

- Install the tetex packages.

Don't install tetex over the old packages with --force**. You will get
an inconsistent system.