Adding background iperf to onosnet.py
Adding background iperf to onosnet.py

Also, doing some other cleanup and improvements

Change-Id: I17ee64126e5e8de986e460641994a279e18c9492

sdnwiselab/onos,gkatsikas/onos,sonu283304/onos,VinodKumarS-Huawei/ietf96yang,opennetworkinglab/onos,osinstom/onos,kuujo/onos,y-higuchi/onos,donNewtonAlpha/onos,VinodKumarS-Huawei/ietf96yang,lsinfo3/onos,LorenzReinhart/ONOSnew,maheshraju-Huawei/actn,gkatsikas/onos,y-higuchi/onos,sdnwiselab/onos,gkatsikas/onos,maheshraju-Huawei/actn,donNewtonAlpha/onos,VinodKumarS-Huawei/ietf96yang,maheshraju-Huawei/actn,opennetworkinglab/onos,VinodKumarS-Huawei/ietf96yang,osinstom/onos,sdnwiselab/onos,kuujo/onos,y-higuchi/onos,mengmoya/onos,Shashikanth-Huawei/bmp,mengmoya/onos,oplinkoms/onos,lsinfo3/onos,LorenzReinhart/ONOSnew,Shashikanth-Huawei/bmp,kuujo/onos,kuujo/onos,kuujo/onos,Shashikanth-Huawei/bmp,Shashikanth-Huawei/bmp,osinstom/onos,sdnwiselab/onos,LorenzReinhart/ONOSnew,donNewtonAlpha/onos,maheshraju-Huawei/actn,osinstom/onos,opennetworkinglab/onos,oplinkoms/onos,mengmoya/onos,opennetworkinglab/onos,VinodKumarS-Huawei/ietf96yang,oplinkoms/onos,LorenzReinhart/ONOSnew,LorenzReinhart/ONOSnew,mengmoya/onos,opennetworkinglab/onos,oplinkoms/onos,kuujo/onos,mengmoya/onos,lsinfo3/onos,sonu283304/onos,oplinkoms/onos,oplinkoms/onos,maheshraju-Huawei/actn,sonu283304/onos,y-higuchi/onos,sonu283304/onos,gkatsikas/onos,Shashikanth-Huawei/bmp,donNewtonAlpha/onos,kuujo/onos,y-higuchi/onos,lsinfo3/onos,osinstom/onos,sdnwiselab/onos,gkatsikas/onos,sdnwiselab/onos,opennetworkinglab/onos,oplinkoms/onos,gkatsikas/onos,donNewtonAlpha/onos