Applied patch from https://bugs.launchpad.net/zope2/+bug/257675, avoiding the mysterious '-C' in request.form

Moved the code handling ZCML loading into the ``Zope2.App`` package. The component architecture is now setup before the application object is created or any database connections are opened. So far the CA was setup somewhat randomly in the startup process, when the ``Five`` product was initialized.

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 ;)