including the merge of `hdffv/hdf5/develop`, back to the branch that Vailin and
I share.
Now I need to put this branch on a fork with a less confusing name than
vchoi_fork!
Deposit the test files in test/misc/testfiles for testh5clear.sh to use instead of depending on h5clear_gentest.
Tested on kituo, osx1010test, quail, platypus and ostrich.