player: fix quit handling when seeking past EOF while paused

The player didn't quit when seeking past EOF in audio-only mode while
paused. The only case when we don't want to quit is when the last video
frame is displayed while paused.

This logic was probably broken a while ago, but I'm not exactly sure.

CC: @mpv-player/stable
TOOLS/youtube-dl_mpv: allow playing multiple URLs

Unfortunately this also means you can't pass extra mpv options after the
URL anymore. You can prefix the script with MPV='mpv --options' though.