Still working on using submodules. Almost done. Current version does not build

.gitmodules

external/nlohmann-json

include/nlohmann/adl_serializer.hpp

include/nlohmann/detail/conversions/from_json.hpp

include/nlohmann/detail/conversions/to_chars.hpp

include/nlohmann/detail/conversions/to_json.hpp

include/nlohmann/detail/exceptions.hpp

include/nlohmann/detail/input/binary_reader.hpp

include/nlohmann/detail/input/input_adapters.hpp

include/nlohmann/detail/input/json_sax.hpp

include/nlohmann/detail/input/lexer.hpp

include/nlohmann/detail/input/parser.hpp

include/nlohmann/detail/iterators/internal_iterator.hpp

include/nlohmann/detail/iterators/iter_impl.hpp

include/nlohmann/detail/iterators/iteration_proxy.hpp

include/nlohmann/detail/iterators/json_reverse_iterator.hpp

include/nlohmann/detail/iterators/primitive_iterator.hpp

include/nlohmann/detail/json_pointer.hpp

include/nlohmann/detail/json_ref.hpp

include/nlohmann/detail/macro_scope.hpp