Add support for trackpad swipe

[ciampo]

References:

• https://github.com/elix/elix/blob/master/src/TrackpadSwipeMixin.js
• https://stackoverflow.com/questions/14086337/is-it-possible-to-have-gestures-with-trackpads
• https://developer.mozilla.org/en-US/docs/Web/API/WheelEvent