A handler class which sends events to the NT Event Log. Adds a
registry entry for the specified application name. If no dllname is
provided and pywin32 installed, win32service.pyd (which contains some basic message
placeholders) is used. Note that use of these placeholders will make
your event logs big, as the entire message source is held in the log.
If you want slimmer logs, you have to pass in the name of your own DLL
which contains the message definitions you want to use in the event log.