Remove most exceptions from getNode() (and variants)
Fix warnings and other misc. minor changes
Merge commit '5b8855e'

Conflicts:
	src/collision.cpp
	src/environment.cpp
	src/game.cpp
	src/localplayer.cpp
	src/map.cpp
	src/map.h
	src/mapblock.cpp
	src/mapblock.h
	src/particles.cpp
Merge remote-tracking branch 'minetest/master'

Conflicts:
	src/emerge.h
	src/mapgen_v6.h
	src/mg_biome.h