Add ABK format description

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Add AMOS Music Bank loader

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Enable AMOS music bank loader

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Implement ABK effects 5, 6, 7, A, D, and 11

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>