Have `field` auto assign if not given (optional field)
Just realilising the elegance coming with the now implemented saqc slicing.
But its spoiled a bit by the redundance of having to assign the field parameter twice always, when operating on "SaQC slices":
qc['new_field'] = qc[field].flagFunc(field, **kwargs)
Couldnt we just make it so, that, when field is not given, it defaults to equaling all the columns in the current saqc object? So that the above call gets equal to:
qc['new_field'] = qc[field].flagFunc(**kwargs)
(also than failing, if, for example, field is a list and flagfunc
cant be called on multiple fields.)