Merge branch 'master' into enhanced_viewport_overlay

Notes on conflict resolution:
* MarkTileDirtyByTile gained an extra param on both sides of the merge
  Move bridge level offset to be after zoom level param, as it's used less.
* Add zoom level params to MarkBridgeDirty functions
* Fix undefined behaviour in colour_index cycling in ViewportMapDraw

Conflicts:
	src/clear_cmd.cpp
	src/pbs.cpp
	src/rail_cmd.cpp
	src/toolbar_gui.cpp
	src/train_cmd.cpp
	src/vehicle.cpp
	src/viewport.cpp
	src/viewport_func.h

src/station.cpp

@@ -106,7 +106,7 @@ Station::~Station()
 		}
 		lg->RemoveNode(this->goods[c].node);
 		if (lg->Size() == 0) {
-			LinkGraphSchedule::Instance()->Unqueue(lg);
+			LinkGraphSchedule::instance.Unqueue(lg);
 			delete lg;
 		}
 	}