ext/wavpack/: Add support for encoding, parsing and decoding multichannel files with up to 8 channels. This also impr...

Original commit message from CVS:
* ext/wavpack/gstwavpackcommon.c:
(gst_wavpack_get_default_channel_mask),
(gst_wavpack_set_channel_layout),
(gst_wavpack_get_default_channel_positions),
(gst_wavpack_get_channel_mask_from_positions),
(gst_wavpack_set_channel_mapping):
* ext/wavpack/gstwavpackcommon.h:
* ext/wavpack/gstwavpackdec.c: (gst_wavpack_dec_reset),
(gst_wavpack_dec_sink_set_caps), (gst_wavpack_dec_chain):
* ext/wavpack/gstwavpackdec.h:
* ext/wavpack/gstwavpackenc.c: (gst_wavpack_enc_reset),
(gst_wavpack_enc_init), (gst_wavpack_enc_sink_set_caps),
(gst_wavpack_enc_set_wp_config), (gst_wavpack_enc_push_block),
(gst_wavpack_enc_fix_channel_order), (gst_wavpack_enc_chain),
(gst_wavpack_enc_rewrite_first_block),
(gst_wavpack_enc_sink_event):
* ext/wavpack/gstwavpackenc.h:
* ext/wavpack/gstwavpackparse.c:
(gst_wavpack_parse_index_append_entry), (gst_wavpack_parse_reset),
(gst_wavpack_parse_scan_to_find_sample),
(gst_wavpack_parse_sink_event), (gst_wavpack_parse_create_src_pad),
(gst_wavpack_parse_push_buffer), (gst_wavpack_parse_loop):
* ext/wavpack/gstwavpackparse.h:
Add support for encoding, parsing and decoding multichannel
files with up to 8 channels. This also improves the robustness
of parsing quite a bit.
* ext/wavpack/gstwavpackstreamreader.c:
(gst_wavpack_stream_reader_read_bytes),
(gst_wavpack_stream_reader_get_pos),
(gst_wavpack_stream_reader_set_pos_abs),
(gst_wavpack_stream_reader_set_pos_rel),
(gst_wavpack_stream_reader_push_back_byte),
(gst_wavpack_stream_reader_get_length),
(gst_wavpack_stream_reader_can_seek),
(gst_wavpack_stream_reader_write_bytes):
Improve debugging.