Make type_index constructor from std::type_info public (fixes #3)

boost/type_index.hpp

@@ -254,18 +254,17 @@ public:
 private:
     const stl_type_info* pinfo_;
 
-    /// @cond
-    explicit type_index(const stl_type_info& inf) BOOST_NOEXCEPT
-        : pinfo_(&inf)
-    {}
-    /// @endcond
-
 public:
     /// Default constructor.
     type_index() 
         : pinfo_(&typeid(void))
     {}
 
+    /// Constructs type_index from an instance of std::type_info.
+    explicit type_index(const stl_type_info& inf) BOOST_NOEXCEPT
+        : pinfo_(&inf)
+    {}
+
     /// Factory method for constructing type_index instance for type T.
     /// Strips const, volatile and & modifiers from T.
     template <class T>