Added a thread safe shared pointer object

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%402530

dlib/smart_pointers/shared_ptr_abstract.h

@@ -39,6 +39,9 @@ namespace dlib
                 This object is not thread safe.  Especially so since it is
                 reference counted.  So you should take care to not have two shared_ptr
                 objects in different threads that point to the same object.
+
+                If you want a thread safe version of this object you should use the
+                dlib::shared_ptr_thread_safe object instead.
         !*/
 
     public:

dlib/smart_pointers_thread_safe.h

+// Copyright (C) 2008  Davis E. King (davisking@users.sourceforge.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+#ifndef DLIB_SMART_POINTERs_THREAD_SAFE_H_
+#define DLIB_SMART_POINTERs_THREAD_SAFE_H_ 
+
+#include "smart_pointers/shared_ptr_thread_safe.h"
+
+#endif // DLIB_SMART_POINTERs_THREAD_SAFE_H_ 
+
+
+