Emit error on stream.

[zigomir]

I was having this issue when I've miss-typed a class name and css-modulesify would silently stop working when using watchify.

My package.json scripts object:

"scripts": {
    "start": "http-server -s & npm run watch-coffee",
    "build": "npm run build-coffee",
    "watch-coffee": "watchify -v -p [ css-modulesify -o dist/starterkit.css ] -t [ hbsfy -e thtml ] -t coffeeify starterkit/src/app.coffee -o dist/starterkit.js",
    "build-coffee": "browserify -p [ css-modulesify -o dist/starterkit.css ] -t [ hbsfy -e thtml ] -t coffeeify starterkit/src/app.coffee -o dist/starterkit.js"
  },

With this change error will emit back to watchify and recover will work as well.

[joshwnj]

Good one, thanks @zigomir