Use CSS scroll snap points for the slider, where available

Detection:
https://developer.mozilla.org/en-US/docs/Web/API/CSS/supports

``` javascript
CSS.supports('(scroll-snap-type: mandatory) or (-webkit-scroll-snap-type: mandatory) or (-ms-scroll-snap-type: mandatory)')
```

Usage:
http://caniuse.com/#feat=css-snappoints
https://developer.mozilla.org/en-US/docs/Web/CSS/scroll-snap-type
https://webkit.org/demos/scroll-snap/
