Let OnHeaders() check the status.
The status checking code was added by commit 4f021cbced in 2011,
but in 2008, commit a8e81326d0 enabled `CURLOPT_FAILONERROR`, which
means the status checking code never had any effect.
This allows `LoadExcludeListOrLog()` to hide boring "404 Not Found"
log messages via `IsFileNotFound()`.
A daemon for playing music of various formats. Music is played through the
server's audio device. The daemon stores info about all available music,
and this info can be easily searched and retrieved. Player control, info
retrieval, and playlist management can all be managed remotely.