DtdAwareContentHandler to support SAX2 LexicalHandler events

[starksm64]

The only way I can get the version for ejb2.x descriptors is to get the doctype. I hacked in some support for this by adding an extended ContentHandler that supports the startDTD/endDTD from the SAX2 LexicalHandler:

 interface DtdAwareContentHandler extends ContentHandler
 {
 public void startDTD(String name, String publicId, String systemId);
 public void endDTD();
 }

The DelegatingContentHandler supports this, and the ObjectModelBuilder and DelegatingObjectModelFactory have been updated to pass this even on based on reflection of the type ObjectModelFactory:

public class BookObjectFactory
 implements ObjectModelFactory
{
 // ObjectModelFactory implementation

 public void startDTD(String name, String publicId, String systemId)
 {
 // Get version info from publicId...
 }