adding container operations for parameter lists, apply_return special case

example/push_args_back.cpp

@@ -0,0 +1,19 @@
+/*<-
+Copyright Barrett Adair 2016
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http ://boost.org/LICENSE_1_0.txt)
+->*/
+
+//[ push_args_back
+#include <callable_traits/push_args_back.hpp>
+
+namespace ct = callable_traits;
+
+int main() {
+
+    using f = void(int, char);
+    using test = ct::push_args_back<f, long, void*>;
+    using expect = void(int, char, long, void*);
+    static_assert(std::is_same<test, expect>::value, "");
+}
+//]