Simplest possible sort impl

This ist the simplest possible sort implementation I found (the one in libc++ is too optimized). 
It allows to at least try the sort interface.

Test using default comparison are provided.

TODO:
- test using iterators, custom comparisons, and projections.
- test file needs cleaning.
We still need a better way to create a range [0, 10) than `ranges::view::take(ranges::view::iota(0), 10);`.

Same issue with `for_each` (can't do `for_each(ints(0,10), ... )` due to rvalue range.

The proposal needs to relax range-based for since it expects iterators with the same type.