(svn r2516) - Feature: [pbs] Implement path-based-signalling. This allows multiple trains within the same signal block, provided their paths dont intersect. For this the block must have all exit and entry signals be pbs signals. Place these by ctrl-clicking 4 times on a normal signal.

- Feature: [pbs] Implement autoplacement of pbs blocks, when a block has an entry and an exit pbs signal, covert the entire block to pbs. Can be turned off in the patch settings.
 - Feature: [pbs] Allow showing of reserved status by making the tracks darker, when the pbs debug level is at least 1.

variables.h

@@ -106,6 +106,7 @@ typedef struct Patches {
 	bool modified_catchment;	//different-size catchment areas
 	bool vehicle_speed;			// show vehicle speed
 	bool build_on_slopes;		// allow building on slopes
+	bool auto_pbs_placement;// automatic pbs signal placement
 	bool mammoth_trains;		// allow very long trains
 	bool join_stations;			// allow joining of train stations
 	bool full_load_any;			// new full load calculation, any cargo must be full