[Glass] GsUpgrader-Core-dkh.121 release

[Dale Henrichs via Glass]

This version contains support for caching the mcz files downloaded 
during `GsUpgrader upgradeGLASS` (gsUpgrader Issue #20[1]).

It's a big step towards being able to do a `createStone` without hitting 
the internet.

The basic idea used for caching in GsUpgrader, is that there will be a 
gsUpgrader directory available in the next release of GsDevKit_home 
(planned for sometime in the next week). When one builds the first stone 
for a particular version of GemStone, the cache will be filled with the 
necessary mcz files while `GsUpgrader upgradeGLASS` is being run. When 
the next stone is built for that version of GemStone, the mcz files used 
by GsUpgrader will all be loaded from the cache directory without 
hitting the internet ..

The GLASS1 load proper still hits the internet, and I will be addressing 
that as I have the time. Keep an eye on GsDevKit_home Issue #54 for info 
and progress.

Other than the fix fot Issue #20[1], `GsUpgrader upgradeGLASS` cointinue 
to run as before.

Dale

[1] https://github.com/GsDevKit/gsUpgrader/issues/20
[2] https://github.com/GsDevKit/GsDevKit_home/issues/54