Upgrade expat to 2.1.0
Remove obsolete expat files
Raise an OSError if xmllint was terminated by the OS.
Merge pull request #803 from mdboom/vo/xmllint-broken

Raise an OSError if xmllint was terminated by the OS.
Fix links from the VOTable validator that point back to warning and exception information in the docs.
Fix test
Merge pull request #781 from mdboom/utils/xml/expat-2.1.0

Upgrade expat to 2.1.0
Merge pull request #806 from mdboom/vo/validation-results-links-broken

Fix links from the VOTable validator
make logo text a theme configuration option