These headers have no associated C files, and are mainly used for
utility logic.
Having them in `/include` makes them more easily located, and more
globally used.
We are using "classic" header guards here over `#pragma once` for better
support. Since `#pragma once` is defined by the compiler, rather than
standard C.
Why isn't it used across the project? I have no idea.
Note: not changing `NBT_I*` macros, since the NBT specification does not
specify a difference between signed/unsigned types. Generally speaking,
internally we treat these as unsigned types for the purpose of
computations being correct.
The unit tests and continious integration is... exessive.
Yes, it's useful, but creates more complications than that it helps, so
it is removed for the time being. Maybe I will add a new framework at a
later date, but at the moment it is constraining development.
