Tidy up core sources:

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

test/core/detail/empty_base_optimization.cpp

@@ -0,0 +1,94 @@
+//
+// 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/detail/empty_base_optimization.hpp>
+
+#include <beast/unit_test/suite.hpp>
+
+namespace beast {
+namespace detail {
+
+class empty_base_optimization_test
+    : public beast::unit_test::suite
+{
+public:
+    template <class T>
+    class test1
+        : private empty_base_optimization<T>
+    {
+        using Base = empty_base_optimization<T>;
+        void* m_p;
+    public:
+        explicit test1 (T const& t)
+            : Base (t)
+        {}
+
+        T&       member()       {return Base::member();}
+        T const& member() const {return Base::member();}
+    };
+
+    template <class T>
+    class test2
+    {
+        void* m_p;
+        T m_t;
+    public:
+        explicit test2 (T const& t)
+            : m_t (t)
+        {}
+
+        T&       member()       {return m_t;}
+        T const& member() const {return m_t;}
+    };
+
+    struct Empty
+    {
+        operator bool() {return true;}
+    };
+
+    static
+    bool
+    test_one ()
+    {
+        test1<int> t1(1);
+        test2<int> t2(2);
+        static_assert(sizeof(t1) == sizeof(t2), "don't optimize for int");
+        if (t1.member() != 1)
+            return false;
+        if (t2.member() != 2)
+            return false;
+        return true;
+    }
+
+    static
+    bool
+    test_two ()
+    {
+        test1<Empty> t1((Empty()));
+        test2<Empty> t2((Empty()));
+        static_assert(sizeof(t1) < sizeof(t2), "do optimize for Empty");
+        if (t1.member() != true)
+            return false;
+        if (t2.member() != true)
+            return false;
+        return true;
+    }
+
+    void
+    run ()
+    {
+        expect (test_one());
+        expect (test_two());
+        pass ();
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(empty_base_optimization,core,beast);
+
+} // detail
+} // beast