gst/matroska/ebml-ids.h: Add ID for EBML CRC32 elements.

gst/matroska/ebml-ids.h: Add ID for EBML CRC32 elements.

Original commit message from CVS:
* gst/matroska/ebml-ids.h:
Add ID for EBML CRC32 elements.
* gst/matroska/Makefile.am:
* gst/matroska/ebml-read.c: (gst_ebml_finalize),
(gst_ebml_read_class_init), (gst_ebml_read_peek_bytes),
(gst_ebml_read_get_length), (_ext2dbl), (gst_ebml_read_float),
(gst_ebml_read_header):
Support reading 80bit floats, add finalize method to clean up
in any case, support reading length/id elements with any length
as long as it's smaller than our supported maximum, don't leak
buffers if reading as much data as we wanted failed and some
smaller cleanup.