I wanted to implement Debug overloads for those already existing 
overloads but then realized that those algos could be generalized. This 
way we will benefit from the memmove replacement when operating with C 
array or std::array or std::vector iterators.

I might do the same for lexicographical_compare one day.

The ChangeLog below is quite huge so I attached it. I wonder if I could 
use deque::iterator and deque::const_iterator in place of the 
_Deque_iterator<> to reduce it ?

Tested under Linux x86_64 normal and debug modes, ok to commit ?

François