parser-postcss parses `@import` at-rules specially, and unfortunately
buggily. This monkey-patches parser-postcss to parse all at-rules the
same way.
Fixes#2584.
postcss-less bug: https://github.com/shellscape/postcss-less/issues/88
The docs go over a bunch of edge cases, might as well have it as a test :)
http://lesscss.org/features/
I just had to remove
```css
.weird-element {
content: ^//* some horrible but needed css hack;
}
```
but i'm not sure if it's real less.
Simon Lydell