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/objdetect/src/datamatrix.cpp

@@ -483,7 +483,7 @@ endo: ; // end search for this o
 #endif
 }
 
-#include <opencv2/imgproc/imgproc.hpp>
+#include <opencv2/imgproc.hpp>
 
 namespace cv
 {