Merge branch 'master' into jgrpp

# Conflicts:
#	regression/regression/result.txt
#	src/aircraft_cmd.cpp
#	src/airport_gui.cpp
#	src/articulated_vehicles.cpp
#	src/console_cmds.cpp
#	src/date_gui.cpp
#	src/engine.cpp
#	src/genworld_gui.cpp
#	src/gfx_layout_fallback.cpp
#	src/group_gui.cpp
#	src/hotkeys.cpp
#	src/network/core/tcp_connect.cpp
#	src/network/core/tcp_listen.h
#	src/newgrf.cpp
#	src/newgrf.h
#	src/newgrf_engine.cpp
#	src/newgrf_gui.cpp
#	src/newgrf_station.cpp
#	src/openttd.cpp
#	src/order_gui.cpp
#	src/os/macosx/osx_main.cpp
#	src/pathfinder/yapf/yapf_node_rail.hpp
#	src/rail_gui.cpp
#	src/saveload/afterload.cpp
#	src/saveload/cargopacket_sl.cpp
#	src/saveload/linkgraph_sl.cpp
#	src/saveload/station_sl.cpp
#	src/script/api/script_industrytype.cpp
#	src/settings.cpp
#	src/settings_gui.cpp
#	src/settings_table.cpp
#	src/settingsgen/settingsgen.cpp
#	src/station.cpp
#	src/station_cmd.cpp
#	src/strings.cpp
#	src/timer/timer_game_calendar.cpp
#	src/timer/timer_game_calendar.h
#	src/timer/timer_manager.h
#	src/timer/timer_window.cpp
#	src/timetable_cmd.cpp
#	src/toolbar_gui.cpp
#	src/town_cmd.cpp
#	src/town_gui.cpp
#	src/train_gui.cpp
#	src/vehicle_cmd.h
#	src/vehicle_gui.cpp
#	src/viewport.cpp
#	src/widgets/dropdown.cpp
#	src/window_func.h
#	src/window_gui.h

src/music/midifile.cpp

@@ -87,7 +87,7 @@ public:
 	 */
 	bool IsValid() const
 	{
-		return this->buf.size() > 0;
+		return !this->buf.empty();
 	}
 
 	/**
@@ -347,7 +347,7 @@ static bool FixupMidiData(MidiFile &target)
 	std::sort(target.tempos.begin(), target.tempos.end(), TicktimeAscending<MidiFile::TempoChange>);
 	std::sort(target.blocks.begin(), target.blocks.end(), TicktimeAscending<MidiFile::DataBlock>);
 
-	if (target.tempos.size() == 0) {
+	if (target.tempos.empty()) {
 		/* No tempo information, assume 120 bpm (500,000 microseconds per beat */
 		target.tempos.push_back(MidiFile::TempoChange(0, 500000));
 	}
@@ -359,9 +359,9 @@ static bool FixupMidiData(MidiFile &target)
 	uint32 last_ticktime = 0;
 	for (size_t i = 0; i < target.blocks.size(); i++) {
 		MidiFile::DataBlock &block = target.blocks[i];
-		if (block.data.size() == 0) {
+		if (block.data.empty()) {
 			continue;
-		} else if (block.ticktime > last_ticktime || merged_blocks.size() == 0) {
+		} else if (block.ticktime > last_ticktime || merged_blocks.empty()) {
 			merged_blocks.push_back(block);
 			last_ticktime = block.ticktime;
 		} else {