Added a version of print_options() that doesn't take an ostream but just prints

to cout.

dlib/cmd_line_parser/cmd_line_parser_kernel_abstract.h

@@ -302,6 +302,18 @@ namespace dlib
                     it will have no effect on the state of #*this.
         !*/
 
+        void print_options (
+        ) const;
+        /*!
+            ensures
+                - prints all the command line options to cout.
+                - #at_start() == true
+            throws                
+                - any exception.
+                    if an exception is thrown then #at_start() == true but otherwise  
+                    it will have no effect on the state of #*this.
+        !*/
+
     // -------------------------------------------------------------
     //                    Input Validation Tools
     // -------------------------------------------------------------

dlib/cmd_line_parser/cmd_line_parser_print_1.h

@@ -23,7 +23,13 @@ namespace dlib
 
             void print_options (
                 std::basic_ostream<typename clp_base::char_type>& out
-            );
+            ) const;
+
+            void print_options (
+            ) const
+            {
+                print_options(std::cout);
+            }
 
     };
 
@@ -47,7 +53,7 @@ namespace dlib
     void cmd_line_parser_print_1<clp_base>::
     print_options (
         std::basic_ostream<typename clp_base::char_type>& out
-    )
+    ) const
     {
         typedef typename clp_base::char_type ct;
         typedef std::basic_string<ct> string;