XIRUSS-T Update: Can store and retrieve XML compound documents

I have finally completed the minimal implementation of support for importing and getting back XML compound documents. This means that from the client you can use the provided XML importer to import an XML compound document (any document using XInclude, an XSD schema, or an XSLT style sheet) and, on the client, request the imported versions and get a DOM from it.

This is the core functionality needed to make XIRUSS-T a useful XML-aware content management system.

I still have more testing to do and more client-side methods to implement but the system is now minimally usable for realistic XML management use cases.

My next tasks, in addition to further testing and method implementation, is to get things packaged up nicely, hack a little client GUI, and start documenting the API and code design in more detail.