Raise the maximum number of bridge types to 16

Raise the maximum number of possible bridge types to 16. The new
bridge types have default properties that make them unavailable at
any year and bridge length, so they cannot be used unless a NewGRF
overrides them.

(cherry picked from commit da399d7bf278ba32fb9f14af65cfcefe5d276e71)

src/bridge.h

@@ -33,7 +33,7 @@ enum BridgePieces {
 
 DECLARE_POSTFIX_INCREMENT(BridgePieces)
 
-static const uint MAX_BRIDGES = 13; ///< Maximal number of available bridge specs.
+static const uint MAX_BRIDGES = 16; ///< Number of available bridge specs.
 
 typedef uint BridgeType; ///< Bridge spec number.
 

src/table/bridge_land.h

@@ -724,7 +724,10 @@ static const PalSpriteID * const * const _bridge_sprite_table[MAX_BRIDGES] = {
 	_bridge_sprite_table_9,
 	_bridge_sprite_table_10,
 	_bridge_sprite_table_11,
-	_bridge_sprite_table_12
+	_bridge_sprite_table_12,
+	_bridge_sprite_table_12,
+	_bridge_sprite_table_12,
+	_bridge_sprite_table_12,
 };
 
 /**
@@ -791,7 +794,11 @@ const BridgeSpec _orig_bridge[] = {
 	   STR_BRIDGE_NAME_TUBULAR_STEEL,        STR_LAI_BRIDGE_DESCRIPTION_RAIL_TUBULAR_STEEL,       STR_LAI_BRIDGE_DESCRIPTION_ROAD_TUBULAR_STEEL),
 
 	MBR(2010, 2, 0xFFFF, 510, 608, 0xA28, PALETTE_TO_STRUCT_CONCRETE,
-	   STR_BRIDGE_TUBULAR_SILICON,           STR_LAI_BRIDGE_DESCRIPTION_RAIL_TUBULAR_STEEL,       STR_LAI_BRIDGE_DESCRIPTION_ROAD_TUBULAR_STEEL)
+	   STR_BRIDGE_TUBULAR_SILICON,           STR_LAI_BRIDGE_DESCRIPTION_RAIL_TUBULAR_STEEL,       STR_LAI_BRIDGE_DESCRIPTION_ROAD_TUBULAR_STEEL),
+
+	MBR(MAX_YEAR + 1, 1, 0, 1, 0xFFFF, 0xA28, PALETTE_TO_STRUCT_CONCRETE, STR_EMPTY, STR_EMPTY, STR_EMPTY),
+	MBR(MAX_YEAR + 1, 1, 0, 1, 0xFFFF, 0xA28, PALETTE_TO_STRUCT_CONCRETE, STR_EMPTY, STR_EMPTY, STR_EMPTY),
+	MBR(MAX_YEAR + 1, 1, 0, 1, 0xFFFF, 0xA28, PALETTE_TO_STRUCT_CONCRETE, STR_EMPTY, STR_EMPTY, STR_EMPTY),
 };
 
 #undef MBR