The old struct config_param remains only for top-level string options.

Eliminate duplicate SidTune construction.

Remove our own songlength database parser.

Eliminates duplicate ParseContainerPath() call.

For type safety and code readability.

This pointer was allocated by libc, not by GLib.

Replacing GLib macros.

Prepare to migrate away from GLib.  Currently, we're still using GLib
as a backend.