[RELEASE] Release of TYPO3 6.2.0alpha1

Change-Id: I85317f149a345b67ddaa6e6d2ec67c90f02a4256
Reviewed-on: https://review.typo3.org/21233
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team
[TASK] Set TYPO3 version to 6.2-dev

Change-Id: I70f9ae0972a71aa4a62c5c99ddc46d7a2f3e3e6d
Reviewed-on: https://review.typo3.org/21234
Reviewed-by: TYPO3 Release Team
Tested-by: TYPO3 Release Team
[TASK] Remove styles for former ExtensionManager

Deleted CSS files that bring styles for former EXT: em.

Change-Id: Ia8bd3c8971ba5aabb7792a08b4cff577d1f95ec6
Resolves: #48550
Releases: 6.2
Reviewed-on: https://review.typo3.org/21073
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters