Dependency on Xerces

[amouat]

I was looking for a quick way to run XML validation when I found your library. Unfortunately, I didn't get it running as it's dependent on Xerces which I would need to find and install separately.

To make things easier for end users, could you either:

1. Rewrite the code to use the JDK XML validation (I think the Oracle JDK bundles a customised version of Xerces), or,
2. Just bundle the Xerces JAR in this repo

Another nice touch would be to create .sh and .bat scripts for running the validator.

Adrian.