heating loads for coils and furnaces not captured in existing heating load output variables

[mpraprost]

when you sum the heating load columns, buildings with gas coils, electric coils, or furnaces show a total heating load of 0. it seems like our existing columns (dx, boiler, vrf, heat_pump, and wa_hp) do not capture heating loads for this equipment.

also, can we change the heat_pump output columns to be "ww_hp" or something along those lines. its a little confusing how it is currently named.