[Vuejs]-Vue import failing

This seems to be because

vuetron/packages/vuetron-plugins/index.js

only exports the default object:

import VuetronVue from './vuetron-vue';
import VuetronVuex from './vuetron-vuex';

export default {
  VuetronVue,
  VuetronVuex
};

For named imports as stated in the docs you would need a named export.