Don't start playback as soon as the "current" song is being loaded
from the state file.  That is unclean, and leads to an obscure bug: in
repeat mode, when the song is started (which is yet the last song in
the list), the playlist code marked the very first song in the
playlist as "next" song, because the end of the playlist was wrapped.

It's easier to set up the playback after all songs have been loaded,
and after the random/repeat mode has been set.