There will only be very few items, and that does not justify the bloat
of std::map.

Fixes linker failure.

Reduce bloat.

Reduce bloat.

For debugging.

Add missing server name prefix.

Don't use std::string, reduce bloat.

Not necessary because we control the LightSong's life cycle.

Zero means "unknown".

Reduce bloat.  We never used the set lookup.

Make this non-fatal.  Just stop reading more objects.