Changed Everything. Stateful just became wax.
I changed the name of the files, the folder, the mixin names, some of
the methods. Here are the basics:
	* model.active() -> model.wax()
	* event "active" -> event "wax"
	* collection.change() -> collection.breathe()
	* stateful-model.js -> model-wax.js
	* stateful-collection.js -> collection.wax.js

The reason for these changes is because I was using the method .active()
and I couldn't find a verb to actually describe what was going on when
you called active. Sometimes it was adding this model, and removing all
others, sometimes it was not removing any, sometimes it was removing the
model you called active on. That just doesn't make sense. Neither does
the name wax() but at least it purposefully makes no sense and I can
fill it with meaning.

Also this should help eliminate this mixin colliding
with common method names .active() and .change() that users may want to
use or are already using in their models and collections. No one is
going to have wax and breathe.

I actually think the wax on, wax off metaphor works decently well with
how we're using this plugin. You perform a wax, by interacting and
trying to change state, the collection listens to the wax event and
breathes, then decides what gets waxed on, and what gets waxed off.