TYPO3 Core

Since TYPO3 CMS 6.0, the XCLASS registration changed and the old
registration style does not work anymore. Additionally, 6.0 comes
with a basic check for old XCLASS registration to warn users about
that.

The patch adds a new report for newly registered XCLASS'es and
adapts the messages to better notify that neither old nor new
registrations are a real problem, but that those classes should
be kept an eye on during upgrading.