unrdered()

[Brian Goetz]

> Although collectUnordered also back propagates lack of order upstream
> (just like forEach, or findAny). To remove collectUnordered we would
> need collectors to define whether they preserve order or not (I see
> in a recent change set to lambda you started work on that).

With
   foo.unordered()....collect()
vs
   foo...collectUnordered()

unless any of the ops in ... inject order (only candidate I can think of 
is sort, when you probably really want the order!), it will be unordered 
for all of the ... ops -- so do we really need the back-propagation?