add BlockSort-Algorithm

[sw-rubix]

https://en.wikipedia.org/wiki/Block_sort
Block sort, or block merge sort, is a sorting algorithm combining at least two merge operations with an insertion sort to arrive at O(n log n) in-place stable sorting. It gets its name from the observation that merging two sorted lists, A and B, is equivalent to breaking A into evenly sized blocks, inserting each A block into B under special rules, and merging AB pairs.