only assign model name from module if not explicitly defined
only assign model name from module if not explicitly defined

LoLab-VU/pysb,alubbock/pysb-legacy,pysb/pysb,neurord/pysb,spgarbet/pysb,jmuhlich/pysb,johnbachman/pysb,alubbock/pysb-legacy,spgarbet/pysb,d-fan/pysb,alubbock/pysb,johnbachman/pysb,alubbock/pysb-legacy,d-fan/pysb,alubbock/pysb-legacy,spgarbet/pysb,neurord/pysb,neurord/pysb,LoLab-VU/pysb,d-fan/pysb