[Zope-CMF] GenericSetup: upgrade step ordering with newer setuptools

[yuppie]

Hi Maurits,

Maurits van Rees wrote:
> 1. In January yuppie did a fix on GenericSetup trunk (r130476), which
> deserves a release, as it fixes upgrade step sort order with setuptools
> 8 and higher.  Thank you, yuppie!

my fix was just a quick and dirty solution relying on legacy code in
setuptools.

> 2. But I just created a branch (maurits-versions-setuptools) with a
> minor fix for that fix, which deserves another pair of eyes.  It avoids
> a warning by pkg_resources.

Your refactoring looks fine.

The code is still a bit hard to read because we convert versions
backwards and forwards: UpgradeEntity.__init__ converts '*' to None and
other strings to tuples, but we no longer use None or tuples. We convert
them back to strings. Is there any third party code that depends on the
old format?


Cheers,

	Yuppie