ROOM_I_ALLOW_STEED      This rooms allows steeds inside, despite any
                        properties that might inhibit steeds from entering.
                        Steeds check for this property by default.
                        This is useful because by default steeds are
                        prohibited from going inside rooms, with this
                        property you can override this feature.
                        See /d/Genesis/steed.c for the handling of illegal
                        and legal destination rooms of the steeds.
