hdf5doc

Changes since 19980720
----------------------

./src/H5Gpublic.h
./src/H5Gprivate.h
./src/H5G.c
./test/dsets.c
./doc/html/Groups.html
	Added the H5Gset_comment() and H5Gget_comment() functions
	described in an earlier e-mail.

./src/H5.c
	Fixed a bug in the tracing code that caused certain data space
	enum types to not be printed.  Nested case statements can get
	confusing to the eyes!

./tools/h5ls.c
	Prints the first 50 bytes or so of object comments.