Clean mapnode.h and fix other files accordingly

src/client.h

src/content_cao.cpp

src/content_mapnode.cpp

src/content_nodemeta.cpp

src/content_sao.cpp

src/farmesh.cpp

src/inventory.cpp

src/inventory.h

src/map.h

src/mapblock_mesh.cpp

src/mapnode.cpp

src/mapnode.h

src/player.cpp

src/player.h

src/server.h