Rework history seletion and removal
Rework history seletion and removal

This fixes the following:
 - auplayer(1) dividing by zero when the history-size is set to zero
 - auplayer(1) exiting when selecting the next playlist entry, after the
   current playlist entry is removed, while a history item is selected.
 - auplayer(1) not moving to the next entry when `d' matches the current
   history item.

kdhp/au-play