Date Parser Revert

Because of IE6/7 test failures that can't be solved without source code changes, I'm reverting the changes in the following commits:

- https://github.com/yui/yui3/commit/02edfa676095eb9c78516eb24ac90d8f5ec7a3cb

- https://github.com/yui/yui3/commit/0dff07d29e478901b873a6654515a12cd6746fdd

- https://github.com/yui/yui3/commit/cf663b78e79444abfb8605d786c57f0f2bbdb521