Description: Improved external link traversal of h5dump. h5dump will now
properly avoid all cycles, even those spanning multiple files. Improvement
to the output of committed datatypes. Committed datatypes are now checked
for uniqueness (like other objects). Tests added for these cases.
Tested: kagiso, linew, smirom (h5committest)
Description: Added -E option to h5ls. When set, this alows h5ls to enter
external files (currently only through an external link). The -r option by
itself will no longer allow h5ls to traverse external links.
Tested: kagiso, linew, smirom (h5committest)
