- Add source map support.
- Add shortcuts to create nodes.
- Method `process()` now returns object with `css` and `map` keys.
- Origin CSS file option was renamed from `file` to `from`.
- Rename `Node#remove()` method to `removeSelf()` to fix name conflict.
- Node source was moved to `source` property with origin file
and node end position.
- You can set own stringify function.