Ressource control for individual components

[sponchcafe]

For more finegrained control over memory and cpu time for components:

1. Memory usage is controlled via the envrionment variable buffer control: Settings has to be added to the component constructor in pysimfs
2. CPU time can be adapted via system nice values (0: max priority - 20: min priority), psutil should do the job
3. Reorganization of the subprocess call may be necessary