updated docs

docs/docs/main_menu.xml

@@ -174,6 +174,10 @@
          <item nolink="true">
             <name>Examples: C++</name>
             <sub>
+               <item>
+                  <name>Linear_Model_Predictive_Control</name>
+                  <link>mpc_ex.cpp.html</link>
+               </item>
                <item>
                   <name>Video_Object_Tracking</name>
                   <link>video_tracking_ex.cpp.html</link>

docs/docs/optimization.xml

@@ -777,6 +777,9 @@ Or it can alternatively solve:
                   by Markus Kogel and Rolf Findeisen
                 </blockquote>
          </description>
+         <examples>
+            <example>mpc_ex.cpp.html</example>
+         </examples>
       </component>
 
    <!-- ************************************************************************* -->