Babel plugin for default module.exports like babel version 5

 Babel@6 doesn't export default module.exports any more. This plugin follows
 the babel@5 behavior - add the module.exports if only the export default
 declaration exists.
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 Babel is a JavaScript compiler to use next generation JavaScript, today.
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 ES2015 and beyond: Babel has support for the latest version of JavaScript
 through syntax transformers. These plugins allow you to use new syntax, right
 now without waiting for browser support.
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 Node.js is an event-based server-side JavaScript engine.