Reset envelopes on new instrument

In FT2, if a new instrument is specified, reset envelopes. See olympic.xm
position 10, channels 14-15. For IT, check if compatible GXX is on.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Reset IT envelopes after previous envelope expired

When playing in IT mode, reset envelopes after the previous envelope ends.

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

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

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