Browser Unpack Example Does Not Work

``` sh
$ browserify x.js y.js > bundle.js
$ browser-unpack < bundle.js | factor-bundle \
x.js -o bundle/x.js \
y.js -o bundle/y.js \
> bundle/common.js
```

`bundle/common.js` is created. Neither `bundle/x.js` or `bundle/y.js` are created. It is my understanding that these bundles should be created with the modules that exist in the common bundle being omitted.
- browserify@11.0.1
- factor-bundle@2.5.0
- browser-unpack@1.1.1

Reproduce los comandos de shell con browserify@11.0.1, factor-bundle@2.5.0 y browser-unpack@1.1.1. Rastrea cómo factor-bundle gestiona la salida de browser-unpack y, a continuación, verifica que se creen bundle/x.js y bundle/y.js omitiendo los módulos compartidos en bundle/common.js.

Escrito por el modelo de indexación a partir del texto del issue.