Merge branch 'master' into jgrpp

# Conflicts:
#	src/aircraft_cmd.cpp
#	src/autoreplace_cmd.cpp
#	src/pathfinder/follow_track.hpp
#	src/pathfinder/yapf/yapf_rail.cpp
#	src/saveload/afterload.cpp
#	src/saveload/saveload.cpp
#	src/script/api/ai/ai_station.hpp.sq
#	src/script/api/game/game_station.hpp.sq
#	src/script/api/script_station.hpp
#	src/track_func.h
#	src/vehicle_base.h

src/pathfinder/yapf/yapf_rail.cpp

@@ -59,6 +59,8 @@ template <typename Tpf> void DumpState(Tpf &pf1, Tpf &pf2)
 	FILE *f1 = fopen("yapf1.txt", "wt");
 	FILE *f2 = fopen("yapf2.txt", "wt");
 #endif
+	assert(f1 != NULL);
+	assert(f2 != NULL);
 	fwrite(dmp1.m_out.Data(), 1, dmp1.m_out.Size(), f1);
 	fwrite(dmp2.m_out.Data(), 1, dmp2.m_out.Size(), f2);
 	fclose(f1);