hdf5_ep

[svn-r773] Changes since 19981019
----------------------

./src/H5Fistore.c
	Improved the hash function so it mixes bits better.  This
	results in a few percent improvement in raw data chunk cache
	efficiency because there are fewer collisions.

./test/chunk.c
	Added #define's for chunk preemption `w0' value and number of
	slots in cache.

./src/H5B.c
	Added some more comments to H5B_insert_helper() and
	H5B_remove_helper()  and also point to some additional
	documentation.