Remove extra fine track volume slide effect

Effect was partly implemented but not used by any format. Remove it.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Fix simultaneous up and down fine volume slide

Change fine volume slide handling so that simultaneous up and down
volume slides are not allowed. This effect is used only in Imago
Orpheus modules.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Fix simultaneous secondary volume up and down

Change secondary volume effect handling so that simultaneous slides up
and down are not allowed. Secondary slide is needed for Impulse Tracker
volume column effects which doesn't share parameters with main slide.

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