Broken vnd errors marshalling tests

The VndErrorsMarshallingTests.jaxbMarshalling() test is broken on Windows with JDK 6, due to platform-specific line separators. The Marshaller produces \n whereas the reference file is read with \r\n. Hence plain String comparison fails.

Solved using xmlunit. I also tried to avoid xmlunit using Node.isEqualNode(), but it failed to recognize the equality, either. So I hope xmlunit as a new test dependency is in order.