Don't create a temporary Song object in handle_lsinfo().  Instead,
print all tags while parsing the remote file.

Don't pass a GError** to g_key_file_get_X().  We don't need to dispose
something we didn't request in the first place.

By accident, this declared a global variable instead of adding the
"packed" attribute.

Explicit attribute initialization.

The MPD core takes care for checking the scheme.