std.range.iota enhancement: supporting more types (AKA issue 10762)

[Jakob Ovrum]

On Saturday, 28 December 2013 at 14:09:17 UTC, Joseph Rushton 
Wakeling wrote:
> Try the attached code.  The largest value of DateTime(2012, 1, 
> 1) + dur!"days"(5
> * n) that is less than DateTime(2013, 1, 1) is _not_ 
> DateTime(2013, 1, 1) -
> dur!"days"(5). :-)

OK, so this has nothing to do with leap years, but that 5.days is 
an improper step.