2005-04-11  Raphael Quinet  <raphael@gimp.org>

	* plug-ins/metadata/metadata.c: Register plug_in_metadata_import
	and plug_in_metadata_export in the PDB.

	* plug-ins/metadata/Makefile.am
	* plug-ins/metadata/base64.h
	* plug-ins/metadata/base64.c: Added base64 decoder, needed for
	reading the thumbnail images (base64 encoded inside XML element).

	* plug-ins/metadata/xmp-parse.h
	* plug-ins/metadata/xmp-parse.c: Added XMP_PTYPE_ALT_THUMBS for
	parsing a list of thumbnail images.  Decode and store the base64
	encoded images.

	* plug-ins/metadata/xmpdump.c
	* plug-ins/metadata/xmp-model.h
	* plug-ins/metadata/xmp-model.c: Added support for thumbnails,
	defined global symbols for standard XMP schema URIs.

	* plug-ins/metadata/interface.c: Preliminary support for widget
	cross-references just for testing - it does not save anything yet.
	Added thumbnail tab, although the thumbnail image is not displayed
	yet.