Merge branch 'master' into jgrpp

# Conflicts:
#	src/cheat_gui.cpp
#	src/industry_gui.cpp
#	src/linkgraph/linkgraphschedule.cpp
#	src/misc/getoptdata.h
#	src/music/dmusic.cpp
#	src/network/core/os_abstraction.cpp
#	src/newgrf_engine.cpp
#	src/openttd.cpp
#	src/order_gui.cpp
#	src/os/windows/win32.cpp
#	src/pathfinder/npf/queue.cpp
#	src/smallmap_gui.cpp
#	src/strgen/strgen.cpp

src/music_gui.cpp

@@ -107,7 +107,7 @@ void MusicSystem::BuildPlaylists()
 	const MusicSet *set = BaseMusic::GetUsedSet();
 
 	/* Clear current playlists */
-	for (size_t i = 0; i < lengthof(this->standard_playlists); ++i) this->standard_playlists[i].clear();
+	for (auto &playlist : this->standard_playlists) playlist.clear();
 	this->music_set.clear();
 
 	/* Build standard playlists, and a list of available music */