Backport 47e01ac from parallelism: D-Bus doesn't seem to depend on a writeable file system.
Backport 2fc2626 from parallelism: Check if a service has started or stopped.

Conflicts:
	usr/lib/yarfi/ServiceThread.py
	usr/lib/yarfi/service.py
Backport 692decc from parallelism: Not importing itself.
Backport aa21ca1 from parallelism: If the service isn't started yet, there could be perhaps no self.process.
Backport 2136deb from parallelism: The check whether D-Bus is running must be in a seperate process.