Merge remote branch 'origin/master'

doc/lua_api.txt

po/pt_BR/minetest.po

src/CMakeLists.txt

src/cavegen.cpp

src/cavegen.h

src/emerge.cpp

src/hud.cpp

src/hud.h

src/mapgen_indev.cpp

src/mapgen_indev.h

src/mapgen_v6.cpp

src/mapgen_v6.h

src/mapgen_v7.cpp

src/mapgen_v7.h

src/scriptapi_object.cpp

src/server.cpp