[TASK] Set TYPO3 version to 7.0.3-dev

Change-Id: I23bb4c6fef0959e6d4d303fed5b8684a2036713a
Reviewed-on: http://review.typo3.org/35235
Reviewed-by: TYPO3 Release Team <typo3v4@typo3.org>
Tested-by: TYPO3 Release Team <typo3v4@typo3.org>