[wavpack] correction file decoding support

Submitted by Kai-Chieh Ku

Link to original bug (#607835)

Description

According to the mailing list (gstreamer-devel), a man told me that current wavpack plugin can not decode WavPack correction files. It can parse those files, though.

Correction files are need to be support because it is the most important feature that other major codecs (e.g. FLAC) don't support.