SortedRange and new docs for std.container

[dsimcha]

== Quote from Andrei Alexandrescu (SeeWebsiteForEmail at erdani.org)'s article
> Hello,
> I just added SortedRange as discussed a while ago in this newsgroup. I
> think it turned out pretty neat. Generally the range abstraction is
> turning out to be very solid.
> To get a SortedRange object for a given range r either call sort(r) if
> you want to sort one, or assumeSorted(r) if you know that the range is
> sorted already.
> I've also fixed Zip (finally!) to get rid of a couple of dirty tricks.
> It turns out that front()/front(v)/moveFront() are a correct way to
> abstract proxy ranges like Zip is.
> Search this documentation preview for "SortedRange" and "Zip":
> http://erdani.com/d/phobos/std_range.html
> http://erdani.com/d/phobos/std_algorithm.html
> I've also improved the look of container requirements, check:
> http://erdani.com/d/phobos/std_container.html
> Comments and ideas are welcome.
> Andrei

One question:  Now that hasAt is gone, how does one use StoppingPolicy.longest
properly?  IMHO StoppingPolicy.longest was never all that useful and should just
be removed.