Tidy up core sources:

The core headers are moved to their own directory (but remain in
the same namespace).

test/core/streambuf_readstream.cpp

@@ -0,0 +1,48 @@
+//
+// Copyright (c) 2013-2016 Vinnie Falco (vinnie dot falco at gmail dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+// Test that header file is self-contained.
+#include <beast/core/streambuf_readstream.hpp>
+
+#include <beast/core/streambuf.hpp>
+#include <beast/unit_test/suite.hpp>
+#include <boost/asio.hpp>
+
+namespace beast {
+
+class streambuf_readstream_test : public beast::unit_test::suite
+{
+public:
+    void testSpecial()
+    {
+        using socket_type = boost::asio::ip::tcp::socket;
+        boost::asio::io_service ios;
+        {
+            streambuf_readstream<socket_type, streambuf> srs(ios);
+            streambuf_readstream<socket_type, streambuf> srs2(std::move(srs));
+            srs = std::move(srs2);
+            expect(&srs.get_io_service() == &ios);
+            expect(&srs.get_io_service() == &srs2.get_io_service());
+        }
+        {
+            socket_type sock(ios);
+            streambuf_readstream<socket_type&, streambuf> srs(sock);
+            streambuf_readstream<socket_type&, streambuf> srs2(std::move(srs));
+        }
+        pass();
+    }
+
+    void run() override
+    {
+        testSpecial();
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(streambuf_readstream,core,beast);
+
+} // beast
+