Checks for proper inheritance from CharacteristicComponent schema,
see http://jira.alma.cl/browse/COMP-3752.
For schema parsing we use the com.sun.xml.internal.xsom classes.
If Oracle removes them, we have to resort to some other library, e.g.
com.sun.org.apache.xerces.internal.xs.XSLoader, http://ws.apache.org/commons/XmlSchema/index.html,
http://www.eclipse.org/modeling/mdt/?project=xsd#xsd
Note that there is a bug in XSOM (checked up to jdk1.7.0_07) that prevents us from first parsing all XSD files
and then validating the baci standards. Thus we parse and validate each schema file separately,
which brings about unnecessary repeated parsing of imported schemas.
The problem is that XSOM does not skip parsing an XSD file when that XSD was already parsed as an imported schema before,
and the other way around. It does however skip an imported XSD that was imported already by a previous schema.
What's broken is the skipping-coordination between imported XSDs and directly parsed XSDs.
The error would be a SAXParseException about "...type... is already defined".