Override icons with the same name
I am loading SVG from 2 different folders. In these folders are SVGs with different names and some with the same name. Webpack throws an error: `Error: The glyph name "foo" must be unique.`
Is there any way that I can tell the loader to override icons with the same name?

``` 
module.exports = {
  files: ['./folder1/*.svg', '../../folder2/*.svg'],
  fontName: 'my-icons',
  classPrefix: 'my-',
  baseSelector: '.myicon',
  types: ['woff2'],
  fileName: 'my.[fontname].[hash:6].[ext]',
}
```
