SpanMode uses incorrect terminology (breadth)

[David Piepgrass]

> Breadth-first (probably never required):
> a/b
> a/c
> a/1.txt
> a/2.txt
> a/b/1.txt
> a/b/2.txt
> a/c/z
> a/c/1.txt
> a/c/z/1.txt
> Defining property: number of /'s increases monotonically. Note 
> how the deeper you go, the more spread out the children become. 
> It's ALL children, then ALL grandchildren, then ALL 
> great-grandchildren, etc.
>
> I wouldn't bother implementing breadth-first. It's doubtful 
> that anyone would want it, surely...?

Actually I prefer breadth-first search when searching the file 
system. When I search an entire volume, inevitably the 
(depth-first) search gets stuck in a few giant, deep directories 
like the source code of Mono or some other cave of source code, 
you know, something 12 directories deep with 100,000 files in it. 
A breadth-first search would be more likely to find the thing I'm 
looking for BEFORE going spelunking in these 12-deep caves.