Adds test for focus when app is initially loaded

This adds an additional test case that ensures the todo input field is focussed when the app initially loads.

Thia relates to the test failures in issue #1034
ampersandjs: add multi-tab sync via storage events, use more efficient subcollection rendering.
Merge pull request #1037 from HenrikJoreteg/master

ampersandjs: add multi-tab sync via storage events
Close #1038 PR: Update vanilla dart.