Adding some safe properties

https://developer.mozilla.org/en-US/docs/Web/CSS/pointer-events

https://developer.mozilla.org/en-US/docs/Web/CSS/image-rendering
https://developer.mozilla.org/en-US/docs/Web/CSS/image-resolution
https://developer.mozilla.org/en-US/docs/Web/CSS/image-orientation

http://www.w3.org/TR/css3-grid-layout/ (it's a draft, but it's mentioned over [here](https://developer.mozilla.org/en-US/docs/Web/CSS/Reference), so I think it also applies - I think it'd be good to support it.)