Merge branch 'master' into jgrpp

# Conflicts:
#	src/signs_cmd.cpp
#	src/station.cpp
#	src/station_cmd.cpp
#	src/town_cmd.cpp
#	src/viewport.cpp
#	src/waypoint.cpp
#	src/waypoint_cmd.cpp

src/signs.cpp

@@ -13,6 +13,7 @@
 #include "signs_func.h"
 #include "strings_func.h"
 #include "core/pool_func.hpp"
+#include "viewport_kdtree.h"
 
 #include "table/strings.h"
 
@@ -46,8 +47,13 @@ Sign::~Sign()
 void Sign::UpdateVirtCoord()
 {
 	Point pt = RemapCoords(this->x, this->y, this->z);
+
+	if (_viewport_sign_kdtree_valid && this->sign.kdtree_valid) _viewport_sign_kdtree.Remove(ViewportSignKdtreeItem::MakeSign(this->index));
+
 	SetDParam(0, this->index);
 	this->sign.UpdatePosition(pt.x, pt.y - 6 * ZOOM_LVL_BASE, STR_WHITE_SIGN);
+
+	if (_viewport_sign_kdtree_valid) _viewport_sign_kdtree.Insert(ViewportSignKdtreeItem::MakeSign(this->index));
 }
 
 /** Update the coordinates of all signs */