Downgrade the ``manage_* is discouraged. You should use event subscribers instead`` warnings to debug level logging. This particular warning hasn't motivated anyone to actually change any code.

Integrated the Products.signalstack / z3c.deadlockdebugger packages. You can now send a SIGUSR1 signal to a Zope process and get a stack trace of all threads printed out on the console. This works even if all threads are stuck.

Revert r110242 - I'm getting strange test failures. Let's not deal with timezone issues on the day before the DST switch ;)

Revert ExtensionClass 2.13 change for now, it breaks CMF tests and we should try to understand what exactly happens here