fix bugs in the soft cascade detect method; add options for debug logging

- WITH_DEBUG_OUT for logging cascade scales
- DEBUG_STORE_IMAGES for xml matrix serialization
- DEBUG_SHOW_RESULT to see detection result

modules/objdetect/include/opencv2/objdetect/objdetect.hpp

@@ -512,7 +512,7 @@ public:
 
     //! return vector of bounding boxes. Each box contains one detected object
     virtual void detectMultiScale(const Mat& image, const std::vector<cv::Rect>& rois, std::vector<cv::Rect>& objects,
-    int step = 4, int rejectfactor = 1);
+    int rejectfactor = 1);
 
 protected:
     enum { BOOST = 0 };