use unordered containers where possible (patch 4 on X)

src/content_sao.cpp

src/content_sao.h

src/guiFormSpecMenu.h

src/map.h

src/mapblock_mesh.cpp

src/mapblock_mesh.h

src/network/serverpackethandler.cpp

src/script/cpp_api/s_async.cpp

src/script/cpp_api/s_async.h

src/server.cpp

src/server.h

src/util/numeric.cpp

src/util/numeric.h