Add support for .iso.wv containers
.iso.wv is the new audio container format becoming popular on the net. It consists of a wavpack image, cue sheet and possibly other files like cover scans, all held within an ISO filesystem image.
While these files are being played by Audacious correctly, they are recognized as a single track. Internal cue sheet is not considered. This is an issue since users cannot choose to play individual tracks within the container.
Reproduced with the latest Audacious 3.7 and wavpack 4.75.2 on Arch Linux.