PCA Puzzle 0.3.5 (room requirements)

New

• Room requirements for add-ons: a mod that supplies rooms can mark a room as unusable and say why, e.g. "needs a furniture mod". /puzzle validate shows the reason as an error, and /puzzle build refuses the layout instead of building an empty room. PCA Puzzle Rooms 0.2.0 uses this for its school rooms and red light rooms.