Update boost to 1.71 and add asio

boost/algorithm/string/constants.hpp

@@ -0,0 +1,36 @@
+//  Boost string_algo library constants.hpp header file  ---------------------------//
+
+//  Copyright Pavol Droba 2002-2003.
+//
+// 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)
+
+//  See http://www.boost.org/ for updates, documentation, and revision history.
+
+#ifndef BOOST_STRING_CONSTANTS_HPP
+#define BOOST_STRING_CONSTANTS_HPP
+
+namespace boost {
+    namespace algorithm {
+
+    //! Token compression mode 
+    /*!
+        Specifies token compression mode for the token_finder.
+    */
+    enum token_compress_mode_type
+    {
+        token_compress_on,    //!< Compress adjacent tokens
+        token_compress_off  //!< Do not compress adjacent tokens
+    };
+    
+    } // namespace algorithm
+
+    // pull the names to the boost namespace
+    using algorithm::token_compress_on;
+    using algorithm::token_compress_off;
+
+} // namespace boost
+
+#endif  // BOOST_STRING_CONSTANTS_HPP
+