[RELEASE] Release of TYPO3 4.5.26

Change-Id: Icf32e527e7c19afe18e2b0ef89dfb9a34ae11942
Reviewed-on: https://review.typo3.org/20450
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team
[TASK] Set TYPO3 version to 4.5.27-dev

Change-Id: I58f86edced0c72436a14ae9ed1ac57a3700bdc62
Reviewed-on: https://review.typo3.org/20451
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team