Bump source compatibility to 1.6 so we can use @Override annotations properly, and fix David's timezone.
Bump source compatibility to 1.6 so we can use @Override annotations properly, and fix David's timezone.

kidaa/truth,dahlstrom-g/truth,andyglick/truth0,cgruber/truth,cgruber/truth,hcoles/truth,andyglick/truth0,google/truth,kidaa/truth,google/truth,dahlstrom-g/truth,hcoles/truth,google/truth