simplify example proposal models
simplify example proposal models

pinax/symposion,pyconca/2013-web,pyohio/symposion,pyohio/symposion,NelleV/pyconfr-test,euroscipy/symposion,toulibre/symposion,euroscipy/symposion,NelleV/pyconfr-test,pydata/symposion,miurahr/symposion,python-spain/symposion,pyconca/2013-web,faulteh/symposion,python-spain/symposion,TheOpenBastion/symposion,miurahr/symposion,pinax/symposion,pydata/symposion,mbrochh/symposion,mbrochh/symposion,toulibre/symposion,faulteh/symposion,pyconau2017/symposion,TheOpenBastion/symposion,pyconau2017/symposion