adds a JPEG-specific thumbnailing function that's faster than the
	exiting thumbnail code. This new code is only included if the
	libjpeg library is present at configure time. We still need RPM
	spec file changes to require this library if we are going to build
	RPMs on systems that have libjpeg. I fixed a few bugs in Alex's
	original patch and made some coding style tweaks as well.

	* acconfig.h:
	* configure.in:
	Added a check for libjpeg.

	* libnautilus-extensions/Makefile.am:
	* libnautilus-extensions/nautilus-thumbnails-jpeg.c:
	* libnautilus-extensions/nautilus-thumbnails-jpeg.h:
	Add new source files with JPEG thumbnailer.

	* libnautilus-extensions/nautilus-thumbnails.c: (make_thumbnails):
	Call the new function for JPEG files.

	Other changes.

	* libnautilus-extensions/nautilus-volume-monitor.c: Change
	interval back to 2 seconds.

	* libnautilus-extensions/nautilus-preferences.c:
	(preferences_set_storage_path): Fix storage l...