Renamed some event attributes to match naming in other parts of billy
Renamed some event attributes to match naming in other parts of billy

openstates/billy,sunlightlabs/billy,openstates/billy,mileswwatkins/billy,openstates/billy,loandy/billy,mileswwatkins/billy,loandy/billy,loandy/billy,mileswwatkins/billy,sunlightlabs/billy,sunlightlabs/billy