Concept revision and documentation (API Change):

The concept type traits are renamed for consistency,
and consolidated into a single header file <beast/core/type_traits.hpp>

A new section, Core Concepts, is added to the documentation describing all
of the core utility classes and functions. This also includes a complete
explanation and sample program describing how to write asynchronous initiation
functions and their associated composed operations.

test/http/nodejs_parser.hpp

@@ -12,8 +12,8 @@
 
 #include <beast/http/message.hpp>
 #include <beast/http/rfc7230.hpp>
-#include <beast/core/buffer_concepts.hpp>
 #include <beast/core/error.hpp>
+#include <beast/core/type_traits.hpp>
 #include <boost/asio/buffer.hpp>
 #include <boost/system/error_code.hpp>
 #include <cstdint>