migrate to "export default"

also, set no-use-before-define in linter

src/test/tasks-test.js

@@ -1,13 +1,13 @@
 /* jslint node:true */
 
 import BoxError from '../boxerror.js';
-import * as common from './common.js';
+import common from './common.js';
 import expect from 'expect.js';
 import fs from 'node:fs';
 import paths from '../paths.js';
 import safe from 'safetydance';
 import tasks from '../tasks.js';
-import * as _ from '../underscore.js';
+import _ from '../underscore.js';
 
 /* global it:false */
 /* global before:false */