onRotateTo callback

[bmuenzenmeyer]

Research feasibility of following:
Either supply an element, which will then trigger callback when that element rotates to/past the given degrees.
If no elements are supplied, will trigger when every element passes the given degrees.

Alternatively: add the compassrose direction back to element orientation and then add a method with a signature like method('id', callback, 50, (80)) which calls callback whenever the id passes the value, or into the value if both supplied