Added polyfills for EventTarget (needed for Safari) and CustomEvent (needed for IE)

src/lib/event_target_polyfill.js

@@ -0,0 +1,9 @@
+import EventTargetPolyfill from '@ungap/event-target'
+
+try {
+  /* eslint-disable no-new  */
+  new EventTarget()
+  /* eslint-enable no-new  */
+} catch (e) {
+  window.EventTarget = EventTargetPolyfill
+}

src/main.js

@@ -2,6 +2,9 @@ import Vue from 'vue'
 import VueRouter from 'vue-router'
 import Vuex from 'vuex'
 
+import 'custom-event-polyfill'
+import './lib/event_target_polyfill.js'
+
 import interfaceModule from './modules/interface.js'
 import instanceModule from './modules/instance.js'
 import statusesModule from './modules/statuses.js'