Load "node-sass" from another directory

Hello!

Thank you for this great plugin!

However, right now, you are using [import-cwd](https://github.com/sindresorhus/import-cwd) to load instance of the `node-sass` from the current working directory. However, we are using our own built tool, which has it's own dependencies located in another directory (separate from the project which is being built).

Is there a way to pass either an instance of the `node-sass` to the plugin directly or use the absolute path to it?

Thanks!