Make similar default typedefs for Point_, Size_ and Rect_

Currently, there are different default typedefs for Point_, Size_, and Rect_. This pull request at least makes sure that default typedefs exist for int, float and double variants of each of these types.

modules/core/include/opencv2/core/types.hpp

@@ -282,6 +282,7 @@ public:
 */
 typedef Size_<int> Size2i;
 typedef Size_<float> Size2f;
+typedef Size_<double> Size2d;
 typedef Size2i Size;
 
 /*!
@@ -349,7 +350,10 @@ public:
 /*!
   \typedef
 */
-typedef Rect_<int> Rect;
+typedef Rect_<int> Rect2i;
+typedef Rect_<float> Rect2f;
+typedef Rect_<double> Rect2d;
+typedef Rect2i Rect;
 
 /*!
   traits