added support in iperf for different result formats. 

also added upper bounds for hifi tests. There were also a few small errors in the tests including:

- didn't take arp into account on link delay test
- needed to convert from percentage to decimal on cpuLimit test
- UserSwitch was not fast enough to have a 5Mbps bandwidth, so changed test to .5 Mbps

fixes #231
fixes #215
Consider that we're looking at the min, avg, and max. I think we should either deal with them separately or set `autoStaticArp=True`.