Idea for more delegations in <algorithm>

[Paolo Carlini]

Chris Jefferson wrote:

> I've had a look at enable_if, and I think we can make use of it still. 
> Unless someone says what is below is pointless / broken, I'll make a 
> clean demo patch sometime tonight / tomorrow. 

Cool! As per my previous message... Just stay away from defaults... By 
the way, if I understand correctly your idea (I have to run now, sorry) 
we have already quite a few "good" usages of enable_if, as return type, 
no defaults, in the library (and only 1 of the "bad" type ;)

Paolo.