originally i tried to match the previous or next song in the playing queue after a load command if the current song was not matched. The idea is ok-ish, but the implementation was broken and become a no-op after some recent refactoring in that area.

while for my particular use-case this has always worked with only "stdio recvfd", sio_open(3) mentions that if no further sio_open calls are made all pledges can be dropped except for "audio", so let's keep it.

now player_playnext has enough information to decide wheter to call player_senderr or player_sendeof.

this will allow to remove the `got_stop' hack in player.c

with the recent refactoring, sndio is only visible in player.c

argc can be -1 if we called noarg with argc=0, because optind is 1.

things like "--" should be skipped etc, easier to rely on getopt(3).

The previous way introduce possible races if multiple `amused' instances try to start the daemon. The new approach is heavily lifted from how tmux does it, but with some minor differences. If the initial connect fails we try to grab a lock to safely execute the daemon only one time. In fact we try to connect one more time even when we hold the lock because another instance can grab the lock, start the daemon and release it between the failure of connect and the first flock. It also changes slightly how the program behaves and how the -d option works. Now running `amused' without arguments is a synonym for `amused status' and the -d option only works if no arguments were given and if the daemon wasn't running.