accdb: stop grouping changesets by key
accdb: stop grouping changesets by key

This fixes unexpected (and inconsistent due to dict randomization)
behavior when one key's changes reference another (copy/move values),
e.g. ["foo<=bar", "-bar"] would be applied in unpredictable order.

(originally commit 054f4191f37b98320c719d5e7292482080bee9c5 in ~/code)

grawity/accdb