Set 'master note' for silent notes on sort mode.
Prevent silent notes to play as ordinary notes in the background
when they are waiting for their turn to arpeggiate.

Remove unnecessary test (it will always return TRUE).

Slower default speed (200ms).

When in sort mode and playing over multiple base notes, in the
beginning of the notes there is a chance that the notes will play
together as an ordinary chord instead of arpeggiate.
This is a regression from 6650dd3.

Fixes #3342