(svn r11534) -Feature(newgrf): Implement property 23h for Industries.

This will add a cost to the removal of an industry using the cheat magic bulldozer.
Note that the removal of regular or newgrf industries without specified removal cost will have no cost applied to.
This is a difference from original spec, where a default base cost is added.

src/newgrf.cpp

@@ -2066,6 +2066,10 @@ static bool IndustriesChangeInfo(uint indid, int numinfo, int prop, byte **bufp,
 				SB(indsp->callback_flags, (prop - 0x21) * 8, 8, aflag);
 			} break;
 
+			case 0x23: // removal cost multiplier
+				indsp->removal_cost_multiplier = grf_load_dword(&buf);
+				break;
+
 			default:
 				ret = true;
 				break;