publicPath failing in Webpack 2
Getting this when I try to build:

`Module build failed: TypeError: Cannot read property 'publicPath' of undefined
    at Object.module.exports (/app/node_modules/webfonts-loader/index.js:146:16)`

So I patched the code directly with better object checking:

`(opts.output && opts.output.publicPath) ? opts.output.publicPath : '/'`

Then it magically seemed to work. Question is, is this just a bandaid for a problem in my setup?