Consolidated upgrade script for 1.6 -> 2.0.

Consolidated upgrade script for 1.6 -> 2.0.

Things still missing:

1. Inserts and other changes to permission.perm_list and
permission.grp_perm_map.  These can't be derived in a simple way from
the individual upgrade scripts, and will have to be hand-crafted to
fit what's already in the seed data.

2. Operations on optional schemas need to be moved out of the
transaction so that the script will work in a database that
doesn't have them.

git-svn-id: svn://svn.open-ils.org/ILS/branches/rel_2_0@17494 dcc99617-32d9-48b4-a31d-7c20da2025e4