Main module headers are moved 1 level up

e.g. <opencv2/core/core.hpp> become <opencv2/core.hpp>

Also renamed <opencv2/core/opengl_interop.hpp> to <opencv2/core/opengl.hpp>

modules/contrib/doc/facerec/src/facerec_save_load.cpp

@@ -16,9 +16,9 @@
  *   See <http://www.opensource.org/licenses/bsd-license>
  */
 
-#include "opencv2/contrib/contrib.hpp"
-#include "opencv2/core/core.hpp"
-#include "opencv2/highgui/highgui.hpp"
+#include "opencv2/contrib.hpp"
+#include "opencv2/core.hpp"
+#include "opencv2/highgui.hpp"
 
 #include <iostream>
 #include <fstream>