Allow event resultHandlers to return a single object instead of an array to make it a bit easier to manage, and change existing events which now do unnecessary array-wrapping.

EventArt fixes: Share the apply/unapply logic for clothes and non-clothes objects to prove that it works and keep it tested.  Improve robustness with partially-defined parameter sets.

Build some event utilities to avoid getting tons of boilerplate in the events, and convert RESS lazy evening to JS as a real single-slave event example.