Document some stitching methods and enable bindings for them.

Author: asmorkalov

modules/stitching/include/opencv2/stitching.hpp

@@ -299,8 +299,13 @@ class CV_EXPORTS_W Stitcher
      */
     CV_WRAP Status stitch(InputArrayOfArrays images, InputArrayOfArrays masks, OutputArray pano);
 
-    std::vector<int> component() const { return indices_; }
-    std::vector<detail::CameraParams> cameras() const { return cameras_; }
+    /** @brief Returns indeces of input images used in panorama stitching
+     */
+    CV_WRAP std::vector<int> component() const { return indices_; }
+
+    /** Returns estimated camera parameters for all stitched images
+     */
+    CV_WRAP std::vector<cv::detail::CameraParams> cameras() const { return cameras_; }
     CV_WRAP double workScale() const { return work_scale_; }
 
     /** @brief Return the mask of the panorama.