Windows service (re-)integration

Windows service (re-)integration

The new args are:

--install[:service_name]
--uninstall[:service_name]
--service

They work as follows:
--install will create a service for you and then terminate.
By default the service name will be "privoxy" (without the quotes).
However you can run multiple services if you wish, just by adding
a colon and then a name (no spaces).

--uninstall follows the exact same rules a --install.

--service is used when the program is executed by the service
control manager, and in normal circumstances would never be
used as a command line argument.