add AllTestsTest for skeleton app

Based on - https://github.com/cakephp/cakephp/issues/2407

I'm honestly clueless what would constitute an acceptance test for test - and I'm open to ideas.  The best I can offer at this time is the classic "works on my machine."

Also, beyond the standard file header, I'm not sure what other boilerplate needs to be added.  Please advise on this too.