migrate to "export default"

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

src/test/locks-test.js

@@ -1,7 +1,7 @@
 /* global it, describe, before, after */
 
 import BoxError from '../boxerror.js';
-import * as common from './common.js';
+import common from './common.js';
 import expect from 'expect.js';
 import safe from 'safetydance';
 import locks from '../locks.js';