fixed and improved test_model_pickle
fixed and improved test_model_pickle

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