Allowing elements to be passed to service

[gmurphey]

I had misread the documentation when setting this up in our app and used this.element when setting up resize detection. This worked great until 0.4.0 was released and when jQuery was removed. I thought it would be nice if the service was still able to accept an element.

[Gaurav0]

@gmurphey Sorry for the delay.

This looks very good!

Can you add a test similar to

ember-element-resize-detector/tests/integration/components/resize-detector-test.js

Line 33 in fa0e6ed

test('it triggers an action when target changes sizes', function(assert){

where you pass an element instead of a selector?