[Feature] Support for clearing the 'complete' cb

[JohnErnstDev]

It would be nice to be able to clear the setTimeout / unbind the transitionEnd before it fires in some circumstances.

Use case would be on a single-page app with a long running animation where the user navigates to another page before the animation completes and the js scheduled to fire on the 'complete' callback is no longer present. The module should be able to ask jquery.transit to unbind the callback.

Nice plugin BTW!