h4h5tools

Purpose:
Handling presence/absence of GZIP/SZIP

Description:
h4h5 tools now reflect that HDF4 can be configured with or without szip,
and HDF5 can be with szip, without szip, or with szip but without szip's
encoder.  Tests that would fail are skipped and warning messages are
printed when HDF5 doesn't have a filter that HDF4 does.

Solution:
Configure script detects filters when it is run to modify test scripts,
and the h4h5 library checks them before it sets them in a property list.

Platforms tested:
sleipnir