Lowering Roofs and Taller Chimneys

@PitlordMaggie I'm testing this as we speak. It looks like there is a way to get sims to walk in, after all: you'd have to build a kind of porch attached to the "second storey on the ground" garage with a stair down to the ground. If you've placed it right, the stair will have just one step and sims will be able to climb it to get to the garage level.