Fixes #996 for now by somewhat improving how column attributes are handled through the ColDefs class.  This caused one test to break, but the behavior expected by the test didn't make much sense to begin with, and the new behavior is much more in line with sensible user expectations.
When passing data to CFITSIO for compression, it must be in native endianness, however, the logic for determining when to do that was wrong for big-endian machines.
VOTable binary format is always in big-endian format.  The logic for determining when to byteswap from memory to the bytestream was wrong on big-endian machines.
Fix the dtype comparison so it is correct on big-endian machines
Fix the dtype comparison so it is correct on big-endian machines
Merge pull request #996 from iguananaut/issue-996

Column.null not used when writing FITS table?
Merge pull request #621 from crawfordsm/master

Added robust statistics to stats
Merge pull request #1003 from mdboom/misc/byteswap-bugs

Fix a number of byteswapping bugs