Support _any_ implementation of the EventTarget interface for addEventListener

[dancrumb]

First: I love this package!

Second, I was a little surprised to learn that addEventListener only supports DOM elements, the window or a media query list as element.

Looking through the code, I couldn't immediately see why it couldn't also support any instance of the EventTarget interface.

I'm happy to create a PR, but I wanted to see if there was a pre-existing reason for the current support limit.

[juliencrn]

Thanks! I'm curious to see your proposal.

[dancrumb]

I created #585, since I think an implementation is probably the clearest proposal :)

Happy to modify, refine, etc.