Plugins that have the capability flag
HWPLUG_CAPS_EXTENSION set are a special plugin type
that doesn't offer any functionality on its own but just extends an existing plugin type.
Certain plugin types support a number of extensions in newer Hollywood versions and the
extension plugin type can be used to tell Hollywood which extensions your plugin actually
supports. There is only one function, GetExtensions(), which
Hollywood will call to get information about the extensions supported by your plugin.
This plugin type is supported since Hollywood 6.0.