can.ui.Accordion API

Options:
- disabled - is the accordion disabled?
- active - the active element
- animated - how to animate
- collapsible
- event - which event triggers the accordion. This should work with select / activate from selectable. Might want it to also work with draghover or what-not.
- header (change from title)
- icons
- prop - a can.prop that has the value of which attr to show / hide

Events
- change - triggered on the DOM with the element that is being shown

Methods
- enable / disable
- activate
- show

Theming
- inherit ThemeRollers