Update documentation

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update module type setting in MOD loader

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Update S3M, XM and IT module type setting

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