range-v3

Experimental range library for C++11/14/17

Range library for C++11/14/17. This code is the basis of a formal proposal to add range support to the C++ standard library. Range v3 is a library for the future C++. Not only does it work well with today's C++ -- move semantics, lambdas, automatically deduced types and all -- it also anticipates tomorrow's C++ with Concepts.