Using Seam's CDI XML extension for CDI and Candi XML as a guide, let's add the ability to do XML config back into the specification.

Annotations and Alternatives should always be the first line of offense for doing injection, decoration and interception. However, there are times when you want to configure things that don't fit well into this model. This is also useful for testing.

This is not to give up type safeness via annotations, but to have some additional flexibility.