Handle statute scope

[mscarey]

Add a way to handle a statement that a Rule applies "for the purposes of the X Act". This seems analogous to assigning a variable to function scope rather than global scope.

A Rule might take Factors with global scope as inputs, and create a Factor with statute scope as an output.

There are also situations where a Rule might explicitly refer to one statute's scope, but a researcher would still want to try to apply the Rule to a fact pattern under some other statute.