fix: support touchStarted, touchEnded, touchMoved

[psugihara]

fixes #22

Hey @LingDong- thanks for this awesome lib. Needed to get touch working for mobile and thought I'd share my solution back.

You use this by setting the handlers on q5:

const q5 = new Q5();
q5.touchStarted = () => {}
q5.touchMoved = () => {}
q5.touchEnded = () => {}

[GoToLoop]

$.touches = [...event.touches].map(getTouchInfo);

Isn't property touches an array already?!

[psugihara]

I think it's a TouchList which doesn't have .map in all implementations.

https://developer.mozilla.org/en-US/docs/Web/API/TouchList

[GoToLoop]

Oh, now I've got it why: $.touches = [...event.touches].map(getTouchInfo);

BtW, the old way to do that is: $.touches = Array.prototype.map.call(event.touches, getTouchInfo);

[psugihara]

Cool. That seems nice bc it doesn't create a new array.