code: function decorate (Comp) {
    var component
  
    // instantiate classes
    if (typeof Comp === 'function') {
      component = new Comp()
    } else {
      // make sure we don't change the id on a cached component
      component = Object.create(Comp)
    }
  
    // components get a new id on render,
    // so we can clear the previous component cache.
    component._durrutiId = String(componentIndex++)
  
    // cache component
    componentCache.push({
      id: component._durrutiId,
      component: component
    })
  
    return component
  }
docs: decorate a basic class with durruti specific properties