Fix missing imports and add tests

packages/common/jsonld.js

 "use strict";
 
-import utils from "./utils";
+import * as utils from "./utils";
 
 let instances = {};
 let successFunctions = {};

packages/common/test/unit.js

 import * as utils from '../utils';
+import '../vpu-mini-spinner.js';
+import '../jsonld.js';
 
 describe('utils', () => {
     it('base64EncodeUnicode', () => {

packages/common/vpu-mini-spinner.js

 import {html, LitElement, css} from 'lit-element';
-import commonUtils from './utils.js';
+import * as commonUtils from './utils.js';
 
 
 class MiniSpinner extends LitElement {