Stable partition3 implementation

[Xinok via Digitalmars-d]

I wanted to get some feedback on a stable partition3 
implementation for Phobos before I work on a pull request. I 
wrote this implementation which is in-place (zero memory 
allocations) but runs in O(n lg n) time.

http://dpaste.dzfl.pl/e12f50ad947d

I found this paper which describes an in-place algorithm with 
O(n) time complexity but it's over my head at the moment.

http://link.springer.com/article/10.1007%2FBF01994842

It is trivial to implement an algorithm with O(n) time complexity 
and O(n) space complexity, but that requires allocating memory. 
Furthermore, using a buffer requires the range to have assignable 
elements.


Any thoughts?