Only reset MED volume if instrument is non-synth

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Change OctaMED octave mapping

Load OctaMED notes directly mapping octave numbers (previously we were
adding 48 to each note). This is needed because newer OctaMED modules
can have notes in higher octaves.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
[test] Update MMD0/3 format reference data

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