Support for .env variables (dotenv)

I use this package to test some of my node.js app during development. Some of the apps uses `.env` variables. For example: `process.env.TWITTER_CONSUMER_KEY`.

To set the values I create a `.env` file in the project's root directory and use the [dotenv](https://www.npmjs.com/package/dotenv) package to read the file. How can we get this working with atom-script as it doesn't seem to read the file during run. If I run the node app via CLI it reads the file.