refactored exposure compensators (opencv_stitching)

modules/stitching/precomp.hpp

@@ -46,14 +46,16 @@
 #include "cvconfig.h"
 #endif
 
+#include <vector>
+#include <algorithm>
+#include <utility>
 #include "opencv2/core/core.hpp"
 #include "opencv2/core/internal.hpp"
 #include "opencv2/imgproc/imgproc.hpp"
-#include "gcgraph.hpp"
 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/features2d/features2d.hpp"
 #include "opencv2/calib3d/calib3d.hpp"
 #include "opencv2/gpu/gpu.hpp"
-#include <vector>
+#include "gcgraph.hpp"
 
 #endif