Merge branch 'master' into jgrpp

Remove the viewport sign cache as this is now superseded by the kd tree
implementation

# Conflicts:
#	src/crashlog.cpp
#	src/lang/english.txt
#	src/misc.cpp
#	src/pathfinder/follow_track.hpp
#	src/pbs.cpp
#	src/rail_cmd.cpp
#	src/saveload/vehicle_sl.cpp
#	src/settings.cpp
#	src/settings_gui.cpp
#	src/ship_cmd.cpp
#	src/station.cpp
#	src/station_base.h
#	src/station_cmd.cpp
#	src/table/settings.ini
#	src/thread/thread_morphos.cpp
#	src/town_cmd.cpp
#	src/train_cmd.cpp
#	src/viewport.cpp
#	src/waypoint.cpp

src/saveload/town_sl.cpp

@@ -28,6 +28,7 @@ void RebuildTownCaches()
 {
 	Town *town;
 	InitializeBuildingCounts();
+	RebuildTownKdtree();
 
 	/* Reset town population and num_houses */
 	FOR_ALL_TOWNS(town) {