Port ZEO changes for Windows from ZODB 3.2.

In addition, repaired the useless default logging in runzeo.py.

Here's Sidnei's Zope 2.7 checkin comment:

* Borrow Zope's 'Signal' mechanism for Windows, if available, to
  implement clean shutdown and log rotation handlers for Windows.

* Back to creating a .PID for ZEO, so external programs that wish to set
  the 'signal' can get the PID and therefore derive the signal name.
  Currently only necessary on Windows but created on all platforms which
  implement os.getpid(), as long as the 'pid-filename' option is set,
  or the 'INSTANCE_HOME' environment variable can be found.