Added a clang-format file so we have ONE uniform formatting going forward.

Make sure you install clang-format
example: npm install -g clang-format as well as a good VS Code Formatter - like Clang-Format by Xaver Hellauer

example of formatting a whole repository that I found useful:
find . -iname "*.hpp" -o -iname "*.cpp" | xargs clang-format -i
or a single file clang-format -i test_unit/test_io.cpp.