Waiting for test-run completion

It's difficult to use the python client for test-run completion. 
One needs to write a bash script that parses the stdout coming out from various commands:
- the one that schedules the job (to extract the job id)
- one that enquires the state of the job (to extract its status)
This cannot be done with python if only, because start_test_run does not return the job id (it only prints it out). 
Since anyone using this client will be interested in knowing when the job is finished, i thought I propose to enable it at the very root and propose this change.