Created new class "DocumentImpl" which represents an XML Document. This
document will eventually implment the DOM Document interface. For now,
it implments all of the functionality that was present in DBReader, plus
cuts down on the number of database calls required to read a document. And
it simplifies the API for interacting with a DOM Document. When the
"toString()" method is called, this class emits the document as an XML
serialization of the DOM structure.
The functionality of DBSAXDocument will be folded into this class as well,
so that we will have one class that can both read documents from the
database and write a document to the database. This functionality is not
yet implmented, however.
Modified MetaCatServlet to utilize this new class instead of DBReader.