Prevent duplication of __source initial condition
Prevent duplication of __source initial condition

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