Fix nearly all warnings

src/collision.cpp

src/emerge.h

src/environment.cpp

src/guiConfigureWorld.cpp

src/guiCreateWorld.cpp

src/guiPasswordChange.cpp

src/guiVolumeChange.cpp

src/map.cpp

src/mapgen_v6.cpp

src/mapgen_v7.cpp

src/player.h

src/scriptapi_env.cpp

src/scriptapi_types.cpp

src/test.cpp

src/voxel.cpp