only show add if the slot is for a talk
only show add if the slot is for a talk

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