Throughput graph for each command

A graph for showing the throughput per second for each command of an experiment.  

Current limitation:
- This graph cannot show the throughput for experiment histories, as the throughput data is currently not saved.
- As the experiment runs, the graph only shows the current calculated throughput value, it does not show how the throughput value changes/varies during a running experiment.  It is a limitation of the current data model, which should be updated to be more dynamic soon.