[jdom-interest] bugs with clone()

[Michael Skells]

There are a number of bugs with the implementations of clone()

1. The implementation of clone in Entity is final, but the class is not
which is not much help for an subclass of Entity and breaks the
specification of clone() from Object.
2. The same is true of CDATA and Comment, Attribute, Document,
ProcessingInstruction

3. Specification of clone() [from Element] is that it should perform a
deep clone. however the implementation of clone() in Entity performs a
shallow clone as does ProcessingInstruction