NzbDrone v1533 - Added SPK compatibility for built-in NzbDrone updates!

SPK now versioned by date for multi-branch and built-in NzbDrone updater compatibility - SPK upgrade now retains current NzbDrone binary (avoids potential binary downgrade) when necessary
Forgot the comment on this one...Before starting a package upgrade process, the Package Center stops the package. So, when you arrive at this point, the package should no longer be running (also means that PID removal should also not be needed)