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Remove the viewport sign cache as this is now superseded by the kd tree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/viewport_func.h

@@ -111,7 +111,6 @@ Point GetViewportStationMiddle(const ViewPort *vp, const Station *st);
 void ShowTooltipForTile(Window *w, const TileIndex tile);
 
 void ViewportMapClearTunnelCache();
-void ViewportClearStationSignCache();
 void ViewportMapInvalidateTunnelCacheByTile(const TileIndex tile);
 
 void DrawTileSelectionRect(const TileInfo *ti, PaletteID pal);