dragZoom directive

directive that wraps : http://google-maps-utility-library-v3.googlecode.com/svn/tags/keydragzoom/2.0.9/docs/examples.html

Main hack thing here is the spec. There is a comment there about it.
callback for specs, could be thought of an event as well. I gave up on trying to spy on map.prototype. enableKeyDragZoom . By all means someone else fix it.