Improve webpack icon support
Improve webpack icon support

There are lots of examples of code that people write two or more ```webpack.config.*.js``` files, like ```webpack.config.development.js``` and ```webpack.config.production.js```. Webpack also recognises automatically ```webpack.config.babel.js``` and transpiles it with Babel before uses it (I actually use this way).

Perhaps someone can use other extension but ```.js```. I gess begining ```webpack.config.``` is pretty good.
file-icons/atom,daltones/file-icons,DanBrooker/file-icons