#168 introduces clone() of rules

[dburgener]

#168

Because of the way lifetimes are handled in rules, introducing the clone() is the expedient way to handle SID extraction, but isn't ideal from a performance standpoint. Ideally, lifetimes inside ValidatedStatements should be cleaned up, but to avoid this clone() and to enable returning the various maps from get_reduced_infos() so we can call generate_sexp() outside and refactor the library API.