Generalize handling of common group names

[mkr-plse]

Currently, the list of treatment groups are customized to a specific usage pattern. e.g., see pull request 12. It will be better to make this configurable

[lazaroclapp]

This is not a list of treatment groups, but of common group names. Meaning cases where it's counterproductive for Piranha to use the treatment condition name to decide what to delete (e.g. '=treated, =enabled`, and so on).

That said, absolutely worth making this a parameter to the checker, with sane defaults.