Added the ability to auto-activate any link.

If the current element contains an href then allow it to be auto activated as well.

This also contains a bug where the class wouldn't be set to active if you are building your urls inside of a ng-href. The timeout fixes this issue.

I also updated the code to clean up any events when the scope is destroyed.
I would rather have $timeout(<fn>, 0); to show that this is just to get it at the bottom of the event loop, and that we aren't waiting for something.