Option to automatically namespace static data

[matheusgrieger]

Expands usage to allow for a single configuration option, namespaced: boolean, so that all static data will be namespaced into $static component property.

This is solely to avoid conflicts with other options and reactive data (same name, for instance), and helps you to remember which data is or isn't reactive.

Also, tried to add type definitions for TypeScript users, but my knowledge is not enough to extend Vue types.

Example usage with option and namespace:

import VueStatic from 'vue-static';

Vue.use(VueStatic, {
  namespaced: true
});

<template>
  <div>
    Reactive data: {{ normalData }}
    Static data: {{ $static.nonChangingValue }}
  </div>
</template>

<script>
export default {
  data() {
    return {
      normalData: 'this will be reactive'
    };
  },
  static() {
    return {
      nonChangingValue: 'this will not'
    };
  }
}
</script>

[samuelantonioli]

Thank you, good idea and clean code.