New files, handling the mapping from mimetypes to backends

New files, handling the mapping from mimetypes to backends

2005-04-18  David Malcolm  <dmalcolm@redhat.com>

	* shell/ev-document-types.h:
	* shell/ev-document-types.c:
	New files, handling the mapping from mimetypes to backends

	* shell/ev-window.c:
	* thumbnailer/evince-thumbnailer.c:
	Use the ev-document-types code

	* shell/Makefile.am:
	Added new convenience library libevbackendfactory_la, containing
	the new mimetype->backend logic; moved the backends into it.

	* thumbnailer/Makefile.am:
	Make the thumbnailer link with the libevbackend.la convenience
	library, rather than having a duplicate of the backend logic here.