Merge branch 'master' into jgrpp

# Conflicts:
#	regression/regression/result.txt
#	src/autoreplace_cmd.cpp
#	src/industry_gui.cpp
#	src/landscape.cpp
#	src/network/network_content.cpp
#	src/newgrf_roadstop.cpp
#	src/pathfinder/yapf/yapf_ship.cpp
#	src/road_gui.cpp
#	src/saveload/ai_sl.cpp
#	src/saveload/saveload.h
#	src/saveload/vehicle_sl.cpp
#	src/station.cpp
#	src/station_gui.cpp
#	src/video/cocoa/cocoa_ogl.h
#	src/video/sdl2_opengl_v.h
#	src/video/video_driver.hpp
#	src/video/win32_v.h
#	src/widget_type.h
#	src/widgets/dropdown.cpp
#	src/widgets/dropdown_type.h
#	src/window.cpp

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,3 +1,13 @@
+<!--
+Commit message:
+
+- Please use Feature / Add / Change / Fix for player-facing changes. E.g.: "Feature: My cool new feature".
+- Please use Feature / Add / Change / Fix followed by "[NewGRF]" or "[Script]" for moddable changes. E.g.: "Feature: [NewGRF] My cool new NewGRF addition".
+- Please use Codechange / Codefix for developer-facing changes. E.g.: "Codefix #1234: Validate against nullptr properly".
+
+See https://github.com/OpenTTD/OpenTTD/blob/master/CODINGSTYLE.md#commit-message for more details.
+-->
+
 ## Motivation / Problem
 
 <!--