Deprecated SlidingTuple, replaced functionality with BufferIterator
* Tuple template now has an additional constructor which calls the functor of a BufferIterator reference to get the pointer to the buffer pointer
* SlidingTuple template was deleted, a Tuple instance has no sliding capability of its own, needs BufferIterator
* Test cases were changed accordingly
* Iterator template instantiates an internal BufferIterator instead of a SlidingTuple