Date parsing reversion

This reverts the following commits:

- https://github.com/yui/yui3/commit/02edfa676095eb9c78516eb24ac90d8f5ec7a3cb

- https://github.com/yui/yui3/commit/0dff07d29e478901b873a6654515a12cd6746fdd

- https://github.com/yui/yui3/commit/cf663b78e79444abfb8605d786c57f0f2bbdb521

This reversion was made as the discussion in #1353 is still ongoing, but failing tests are still happening even after code freeze for this release.  These commits will be reverted once the discussion in #1353 is finished, and the failing tests are resolved.