Merge branch 'master' into jgrpp

# Conflicts:
#	os/macosx/notarize.sh
#	src/3rdparty/CMakeLists.txt
#	src/3rdparty/squirrel/squirrel/sqcompiler.cpp
#	src/3rdparty/squirrel/squirrel/sqdebug.cpp
#	src/3rdparty/squirrel/squirrel/sqvm.cpp
#	src/console_cmds.cpp
#	src/core/span_type.hpp
#	src/crashlog.cpp
#	src/currency.h
#	src/date_gui.cpp
#	src/driver.cpp
#	src/fios.cpp
#	src/genworld_gui.cpp
#	src/hotkeys.cpp
#	src/misc_gui.cpp
#	src/music/os2_m.cpp
#	src/network/core/os_abstraction.h
#	src/network/network_server.cpp
#	src/newgrf.cpp
#	src/newgrf_config.h
#	src/newgrf_text.cpp
#	src/openttd.cpp
#	src/os/macosx/font_osx.cpp
#	src/os/macosx/misc_osx.cpp
#	src/os/os2/CMakeLists.txt
#	src/os/os2/os2.cpp
#	src/os/unix/CMakeLists.txt
#	src/os/windows/font_win32.cpp
#	src/os/windows/win32_main.cpp
#	src/saveload/saveload.cpp
#	src/script/api/script_text.cpp
#	src/settings.cpp
#	src/settings_gui.cpp
#	src/stdafx.h
#	src/strings.cpp
#	src/timetable_gui.cpp
#	src/town_gui.cpp
#	src/train_cmd.cpp
#	src/video/dedicated_v.cpp
#	src/video/video_driver.cpp
#	src/video/win32_v.cpp
#	src/viewport.cpp
#	src/waypoint_gui.cpp
#	src/widgets/dropdown_type.h
#	src/window.cpp
#	src/window_gui.h

src/core/span_type.hpp

@@ -93,6 +93,14 @@ public:
 	constexpr const_iterator cbegin() const noexcept { return const_iterator(first); }
 	constexpr const_iterator cend() const noexcept { return const_iterator(last); }
 
+	constexpr reference operator[](size_type idx) const { return first[idx]; }
+
+	constexpr span<element_type> subspan(size_t offset, size_t count)
+	{
+		assert(offset + count <= size());
+		return span(this->data() + offset, count);
+	}
+
 private:
 	pointer first;
 	pointer last;