Update Measure variable names to meet PEP8

[rstarmer]

Metrics names were re-worked to be PEP8 compliant as they
are leveraged when defining performance management interactions
and so need to be valid Python variables. The #TODO was also
removed

[rstarmer]

@pnickolov @ekalosak Can you please review and merge if acceptable.

[ekalosak]

lgtm, converted spaces to underscores, a win in my book.

[pavel-georgiev]

Not sure what you mean by performance management interactions , but if you are trying to use these in formulas, you can use metrics['my_metric'] instead of my_metric.

[rstarmer]

@pavel-georgiev That is what I meant, and I wasn't aware of the array name being returned. I still think this is easier, especially for someone wanting to work with a single parameter.