Update properties cache & notify property streams on service going up

[zeenix]

Currently if a service is down when you create a proxy and property streams with it, you won't get the values of the properties or get notified of property changes when the service goes up. A similar thing happens if the service goes down after a successful properties' cache update and notifications: after re-launch the cached values will most likely now be obsolete and need to be re-fetched.