First implementation of getStyleInfo

getStyleInfo returns a simplified JSON format to make it easier to convert to CSS
jslint "bitwise" and jshint "bitwise" are opposites, which is weird. We want to use jshint comments everywhere.

Also, jshint temporary changes should be indented at the same level as the code. So, please change these three lines to:

```
            /* jshint bitwise: false */
            if ((fill.reverse !== true) ^ (fill.type === "radial")) {
            /* jshint bitwise: true */
```