(svn r23860) -Feature: [NewGRF] Add cargo property 1D to set the capacity multipliers when refitting vehicles, which do not use callback 15.

src/cargotype.h

@@ -59,6 +59,7 @@ struct CargoSpec {
 	uint8 legend_colour;
 	uint8 rating_colour;
 	uint8 weight;                    ///< Weight of a single unit of this cargo type in 1/16 ton (62.5 kg).
+	uint16 multiplier;               ///< Capacity multiplier for vehicles. (8 fractional bits)
 	uint16 initial_payment;
 	uint8 transit_days[2];