std.algorithm imporvments

[monarch_dodra]

On Monday, 16 July 2012 at 22:42:47 UTC, Andrei Alexandrescu
wrote:
> Wow, this is awesome. Did you discover that by inspection or by 
> testing? I think a "malicious input range" would be a great 
> tool for assessing which algorithms fail on input ranges.
>
> Andrei

The first I discovered testing with a "ConsumableRange",
actually. The second, I found by inspection.

I'll correct those two issues myself, but I don't feel
comfortable with the other issues.