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Remove the viewport sign cache as this is now superseded by the kd tree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/company_gui.cpp

@@ -523,8 +523,6 @@ class DropDownListColourItem : public DropDownListItem {
 public:
 	DropDownListColourItem(int result, bool masked) : DropDownListItem(result, masked) {}
 
-	virtual ~DropDownListColourItem() {}
-
 	StringID String() const
 	{
 		return this->result >= COLOUR_END ? STR_COLOUR_DEFAULT : _colour_dropdown[this->result];
@@ -540,7 +538,7 @@ public:
 		return true;
 	}
 
-	void Draw(int left, int right, int top, int bottom, bool sel, int bg_colour) const
+	void Draw(int left, int right, int top, int bottom, bool sel, Colours bg_colour) const
 	{
 		bool rtl = _current_text_dir == TD_RTL;
 		int height = bottom - top;