Improve coverage exclusion specificity

[ngraymon]

To distinguish between:

• debug statements that do not need to be covered
• excited state cases that are not supported yet
• legacy code that might need to be kept around
• other?

We can define pragma: <anystring> and as along as its included the .coveragerc file as a regex under exclude_lines = then it will prevent coverage. But by using multiple instances of <anystring> we can communicate more information.