rusage: improve cpu load meassurements
rusage: improve cpu load meassurements

Get the number of cpus and scale process cpu-load accordingly. Switch the
cpuload to be per-mille to get smoother graphs. Add a bit more logging and use
the _OBJECT variant.

shelsonjava/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer