Export as IIFE for UNPKG

[VanishMax]

For now, the directive can be installed just as a directive. But it would be better to export as a Vue plugin with install function that would register a directive globally. Just like this:

export default {
  install (Vue, options) {
    Vue.directive('vue-click-outside', {
      bind () { ... all the logic here ... }
    }
  }
}

And later on, bundle for different formats. It would any person use the directive in any format they want. But for now... Looks like I have to migrate for another click-outside.