message: include view/set_algorithm.hpp in view.hpp
  Not sure whether the original code is intended, it looks like overlook to me. test plan: Travis-CI
diff: @@ -52,6 +52,7 @@ RANGES_DISABLE_WARNINGS
  #include <range/v3/view/replace_if.hpp>
  #include <range/v3/view/reverse.hpp>
  #include <range/v3/view/sample.hpp>
  +#include <range/v3/view/set_algorithm.hpp>
  #include <range/v3/view/single.hpp>
  #include <range/v3/view/slice.hpp>
  #include <range/v3/view/sliding.hpp>
  