gst/wavparse/gstwavparse.c: When operating chain-based, don't make any assumptions about the chunking of the incoming...

Original commit message from CVS:
* gst/wavparse/gstwavparse.c: (gst_wavparse_peek_chunk_info),
(gst_wavparse_peek_chunk), (gst_wavparse_stream_headers),
(gst_wavparse_chain):
When operating chain-based, don't make any assumptions about the
chunking of the incoming data and make streaming work on days other
than the second Thursday after a full moon. Also fix up debug
messages here and there and make use of the most excellent new
gst_pad_query_peer_duration() utility function.
Skip any 'bext' chunks in front of the 'fmt ' chunk. Fixes #343837.
* gst/wavparse/gstwavparse.h:
Remove trailing comma after last enum value, some compilers don't
like that.