add __init__.py for examples package
add __init__.py for examples package

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