Lots of changes.

1.Added Utf8 String.
2.Added RINLINE macro to OO.h.(force inline)
3.String speed up.
4.Added func 'Base64_Decode_Int12' to Base64.
5.Added Tune_ namespace to enum Tune_PitchNameMode.
6.Fixed some bugs.
Do not change this function. Consider the following scenario:

    char Temp[3];
    Temp[0] = "a";
    Temp[1] = "b";
    Temp[2] = "c";
    String_SetCharsN(& Str, Temp, 2);