Added pom.xml with dependencies
Created package-info.java and copied MultiBaseUriResolver.java
Adding documentation to XmlSchemaMultiBaseUriResolver.java.
Defining the XmlDatumReader and XmlDatumWriter for reading and writing
XML documents from/to an Avro stream, respectively.

Adding the Avro <-> Protobuf conversion tool for reference.
Utility for namespace generation.  This will likely need to move.