Experiment might stop before all data arrived

[phip123]

The current issue is, that the Galileo recorder stops recording as soon as the experiment ends (exp.stop).
This is no problem when the Galileo Shell is started on a host that has high network bandwidth but becomes problematic as soon as the experiment is started far away or on devices with low network bandwidth.

Solution: extend the Experiment.stop method, such that it waits for any incoming traffic before shutting down.