refactor so core render can be called with an explicit species list
refactor so core render can be called with an explicit species list

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