chapter285, [SORA][SORA Prediction system] implement string class.

It’s finally time to control the drives.
Therefore, we use Windows API a lot (about Windows version),
but Windows uses wchar_t * for internal processing of strings.
Of course, char * can also be used,
but since not all are supported, Windows API mainly uses wchar_t *.

By the way,
we have prepared a class that can freely process wchar_t * and char *.
Now that we can write without worrying about it.