resolves the issue with:
java: brooklyn.entity.rebind.Rebindable cannot be inherited with different arguments: <brooklyn.mementos.EntityMemento> and <>

This is done by dropping generics for the Rebindable, but relying on coveriant return types for getMementoSupport. Provides the same typesafety, at the price of a bit more code.
Merge pull request #670 from pveentjer/0.5

resolves the issue with: