Preliminary work for fiber sort algorithm. This is a naive implementation but suffices for now.
Added Base::ForIter<> lookup template to <base/stl_utils.h>.  The standard doesnt
currently have a 'right' way to refer to the type returned by dereferencing an
STL-compatible iterator.  Because that includes native pointers, using something
like iter_t::value_type isn't going to work.  So this lookup template is the
place to go and we'll keep it up-to-date with whatever the standard eventually
decides to do about this.
Did some cosmetic stuff here and there, but mostly changed the templates
to use Base::ForIter<> to lookup the type returned by the iterators.
Also dropped the use of class as a template parameter declarator in favor
of typename.
Merge pull request #41 from JasonL9000/my_pr_40

first stab at parallel sort