Refactored generic functionality in HierarchicalPicoContainer up in the superclass (which has been renamed from AbstractPicoContainer to DefaultPicoContainer)
o Removed caching. It was evil, since it exposed internal state o More null checks in AggregatingContainersContainer (plus a default one-arg subclass) o Commented out unused argument is ParameterSpec inner class
o Used assertSame instead of assertEquals where object identity is meant to be used o Added a FilterContainer class (should maybe move to nano) o Typo fix in method name