cpp/memory/scoped allocator adaptor/scoped allocator adaptor

@1@ Default constructor: value-initializes the base class and the inner allocator member object, if used by the implementation.

@2@ Constructs the base class from, and the inner allocators with. .

@3@ Copy-constructor: initializes each allocator from the corresponding allocator of

@4@ Move-constructor: moves each allocator from the corresponding allocator of into

@5@ Initializes each allocator from the corresponding allocator of. .

@6@ Initializes each allocator from the corresponding allocator of, using move semantics. .