[phobos] isSafelySlic(e)able

[Andrei Alexandrescu]

I think the better way to go is to remove isSafelySlic(e)able and 
instead have hasSlicing return false for narrow strings. Slicing is 
supposed to work with ranges under the assumption that the range is 
random access and the slice indices represent element indices, which is 
not the case for narrow strings.

Thanks Lars for pressing this issue - it was overdue.


Andrei