Detect all scope violations in development mode

_From [kevinb9n](https://code.google.com/u/113026104107031516488/) on July 03, 2007 16:45:45_

Proxy objects in a given scope during development and throw an exception if
the object is used out of scope.

This used to be issue 11 , but that issue got repossessed for another purpose.

This is extremely important as a lot of really nasty bugs are getting into
people's code right now.

_Original issue: http://code.google.com/p/google-guice/issues/detail?id=127_