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/videostab/src/precomp.hpp

@@ -51,11 +51,11 @@
 #include <iostream>
 #include <ctime>
 #include <algorithm>
-#include "opencv2/core/core.hpp"
-#include "opencv2/imgproc/imgproc.hpp"
-#include "opencv2/video/video.hpp"
-#include "opencv2/features2d/features2d.hpp"
-#include "opencv2/calib3d/calib3d.hpp"
+#include "opencv2/core.hpp"
+#include "opencv2/imgproc.hpp"
+#include "opencv2/video.hpp"
+#include "opencv2/features2d.hpp"
+#include "opencv2/calib3d.hpp"
 
 // some aux. functions