Remove logic treating clusters like groups
Remove logic treating clusters like groups

Clusters aren't groups and should not be treated as such.

linus-sherrill/sprokit,Kitware/sprokit,linus-sherrill/sprokit,linus-sherrill/sprokit,mathstuf/sprokit,Kitware/sprokit,mathstuf/sprokit,mathstuf/sprokit,Kitware/sprokit,linus-sherrill/sprokit,Kitware/sprokit,mathstuf/sprokit