Breaking: Add autoprefixer

Depends on https://github.com/cargomedia/puppet-cm/pull/65

Breaking changes:
- Removed mixins: `.box-sizing`, `.user-select`, `.transform`, `.transition`, `.appearance`, `.background-size`, `.hyphens`, `.transform-origin`
- Changing signature of `CM_Asset_Css::__construct`

Upgrade regexp:
```
\.(box-sizing|user-select|transform|transition|appearance|background-size|hyphens|transform-origin)\(.+\)
```
```
$1: $2
```