hdf5_ep

[svn-r5230] Purpose:
    Code cleanup

Description:
    Clean up the H5B_iterate code to not have a single hard-wired iterator for
    each interface which uses a B-tree, instead accept a function pointer which
    determines the callback function.  This allows additional iterator
    callbacks to be defined without requiring additional H5B functions to be
    created.

    In that spirit, remove the H5B_prune_by_extent call and convert the
    H5F_istore callback routine for it into a callback routine for H5B_iterate.

Platforms tested:
    FreeBSD 4.5 (sleipnir)