Webpack issue from version 0.23 to 0.24

### Guidelines for posting a new issue
On version `0.23`

git checout 0.23.2
npm run prepublish

The output in `dist/react-slic.js` will start with

```
(function webpackUniversalModuleDefinition(root, factory) {
if(typeof exports === 'object' && typeof module === 'object')
module.exports = factory(require("react"), require("react-dom"));
else if(typeof define === 'function' && define.amd)
define(["react", "react-dom"], factory);
else if(typeof exports === 'object')
exports["Slider"] = factory(require("react"), require("react-dom"));
else
root["Slider"] = factory(root["React"], root["ReactDOM"]);
})(this, function(__WEBPACK_EXTERNAL_MODULE_2__, __WEBPACK_EXTERNAL_MODULE_4__)
^
|
NOTE: in this version we had this which is ok considering libraryTarget: "umd",
```

But now with the webpack we got:
```
deleted: src/less/atoms/reset.less │npm ERR!
(function webpackUniversalModuleDefinition(root, factory) {
if(typeof exports === 'object' && typeof module === 'object')
module.exports = factory(require("react"), require("react-dom"));
else if(typeof define === 'function' && define.amd)
define(["react", "react-dom"], factory);
else if(typeof exports === 'object')
exports["Slider"] = factory(require("react"), require("react-dom"));
else
root["Slider"] = factory(root["React"], root["ReactDOM"]);
})(window, function(__WEBPACK_EXTERNAL_MODULE__2__, __WEBPACK_EXTERNAL_MODULE__4__)
^
|
in this case we got window which does generate issue width server side rendering
```