CSS3 Cursors

I've added the data for CSS3 cursors to support [an issue with Autoprefixer](https://github.com/ai/autoprefixer/issues/106). I pulled the data straight out of an MDN table. I wasn't sure what to do about mobile browsers since this feature isn't applicable to them. This is my first time contributing to caniuse.com, so please let me know what I'm doing wrong.