GestureHandler doesn't fire "tap" for IE<11

GestureHandler doesn't work for IE 10 and below. In [famous-carousel](https://github.com/peacechen/famous-carousel), I've worked around it by calling this directly on the DOM element when IE is detected:

```
arrowEl.attachEvent("onclick", emitPageChange);
```

MS docs say addEventListener should work for IE 9+, but this doesn't seem to be the case. I could only get it to recognize clicks by calling attachEvent.

I loathe IE as much as anyone, but there are still a lot of systems running IE 9 & 10 and Famo.us does run on them for the most part. I looked through the engine code and from what I can tell, DOMElement.prototype.on() might be the place to modify. Would something like this be better placed under polyfills, if the Famo.us team finds it acceptable?