Title: About Decorators

Describe the issue:
I think it should be mentioned that a Decorator must have exactly one @Delegate injection point to obtain a reference to the decorated object. 

Also, it should be mentioned, that, just like Interceptors, Decorators require to be explicitly enabled in beans.xml.

Inspiration for both these additions can be obtained here: 
http://docs.oracle.com/javaee/6/tutorial/doc/gkhqf.html