Fix forced lowercasing of forwarding_class values
Fix forced lowercasing of forwarding_class values

Forwarding class should be exempt from forced lower_casing of grouped results.  Adds an optional arg to _Group() to skip lowercasing of returned result.
rarcotvmw/capirca,rarcotvmw/capirca,google/capirca,google/capirca,rarcotvmw/capirca,google/capirca,google/capirca