uses anonymous template parm in is_tuple_like
Flattens chain

Chain is flattened using a similar approach to starmap.  A different
instantiation of each ChainIterWrapper for each index.  This avoids
having a nested class structure, and the time to perform operator*
doesn't increase as one gets further into the chain.  An index keeps
track of which iterator we're on each step of the way.

It's not very pretty though.
Grabs PATH from environment
removes return 0
corrects include guard
Merge branch 'master' into cpp14
Merge branch 'cpp14' into indexedchain
adds chain iterator copy ctor
Replaces polymorphic solution with std::functions

..which are also polymorphic, but it allows for a single const static
array per instatiation of TupleStarMapper
Computes callers as constexpr

I did it constexpr.  I'm pretty happy with this, I can't see it getting
much better outside of not writing the code at all.
adds test for iterator assignment to chain
Uses constexpr array of funcion pointers for chain

Instead of the polymorphism and the base class, I was able to use a
similar approach as in starmap to get chain to act more dynamic than it
really is.  Starmap needed only one set of function pointers, for the
dereferencing, chain is admittedly more complicated because it needs one
for each operation that must be performed per iterator.
Merge branch 'cpp14' of https://github.com/ryanhaining/cppitertools into cpp14

Conflicts:
	starmap.hpp