Addressed issue raised on mailing list:
https://www.mail-archive.com/devlivy.incubator.apache.org/msg00295.html
More info on the vulnerability:
https://snyk.io/blog/nokogiri-xxe-vulnerabilities/
Author: Alex Bozarth <ajbozart@us.ibm.com>
Closes #75 from ajbozarth/fix.
Alex Bozarth