This new script makes it easy to compare the current definitions
of events and other types against a chosen base, e.g. the current
state of the master branch or a previous edition. It produces diff
commands that can be run to produce the wanted comparison.

Since figuring out the most recent version of each type is a pretty
common operation, a new versions module is introduced for this purpose.
The existing find-latest-schemas.py script has been adapted to use the
new module.

…r/current