API to iterate the objects in a scope

_From [james.strachan](https://code.google.com/u/112396942773084026914/) on April 06, 2009 06:01:16_

For background see this thread... http://groups.google.com/group/google-guice/browse_thread/thread/da6af0961cf4a5d6 the issue is to be able to find all the objects in a scope easily so that they can be then closed.

Dhanji's great suggestion - is another implementation option - though it requires finding the
binding for the current injectee object in the InjectionListener... https://code.google.com/p/google-guice/issues/detail?id=62 So this patch just allows the provider created by a Scope to also implement the CachedValue
interface so you can ask for the current cached value in a scope.

_Original issue: http://code.google.com/p/google-guice/issues/detail?id=354_