Better error messages

[nfrade]

Would be great if we had a more descriptive error message.
I probably added some useless text somewhere but can't find it:

(...)|feature/postcssify⚡ ⇒ npm run browserify

> (...)@1.0.92 browserify /(...)
> browserify ./platform/main.js -o browserifyBundle.js --debug -r ./package.json:package.json -p [ postcssify --filePlugins postcss-imp
ort --filePlugins postcss-import-url --plugins postcss-cssnext --out browserifyBundle.css ]

Nooo TypeError: Cannot read property 'buf' of undefined
    at /Users/(...)/node_modules/postcssify/lib/index.js:179:58
    at process._tickCallback (node.js:368:9)