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.
`U8String` may be a better name.
Please rewrite it and combine with String class using RTemplate.
Rule: any code repetition longer than 10 lines is a disaster.