[development] update.php for D6

[Barry Jaspan]

This week I have put a lot of hours into fixing all the problems with 
update.php from D5 to D6 (I've been on the road giving a week-long 
Drupal training, with nothing to do in the evenings ;-).  The fruits 
of my labors are at http://drupal.org/node/157682.  It is still in 
code-needs-work status.  I am announcing the issue here for two reasons:

1.  I want to avoid someone else duplicating this work and either 
wasting their time or causing my time to be wasted.

2.  The patch contains a large number of small changes, mostly all 
over system.install.  I'd like to get the review process going 
ASAP.  The "needs-work" parts are things I haven't gotten to yet, but 
the things I have gotten to are "done" and ready for review.  If some 
people familiarized themselves now with all the issues involved, once 
it hits CNR it won't take forever to get committed.

This is also a great opportunity to familiarize yourself with the 
contrib schema.module and its database inspection and comparison capability.

Thanks,

Barry