Add support for "click to zoom"

[erikhansen]

Magento 2 uses Fotorama + Magnifier.js for its default image library. You can see a Magento 2 page here: http://magento2-demo.nexcess.net/cassius-sparring-tank.html (click on the image and then scroll on top of the image to see Magnifier JS at work).

If you click on the image this page to open the full screen view and then click on the image, you'll see the kind of image zoom I'd like to be able to enable: https://www.magictoolbox.com/magiczoomplus/

It would be great if Magnifier JS had the ability to allow a user to "click to zoom", as using the scroll wheel is not intuitive for many users. Since Magento 2 will be used by tens of thousands of merchants, this added feature will benefit many users.

[calvintwr]

1. I think clicking to zoom is okay but I can't say for sure if it's the right statement to make when you say "scrolling is not intuitive". Because google earth uses that.

2. The much bigger problem to address is magento's pinch zooming on mobile phones. And in fact, mac users and some window uses have touchpad that recognises pinch zooming. So it must be also imperative to fix pinch zooming.