Add graphing to TestController UI

Replacing #64 with this PR to target dev branch
This PR should not be merged until after #67
@davidfowl @abnanda1 
It is assigned in the 'updatePerfCounters' hub method and used by the Home/Index.cshtml view. At this time it simply displays a list of counter names and values in a table, but this is likely to change as the UI is refined.