move gpu version of soft cascade to dedicated module

samples/gpu/softcascade.cpp

@@ -1,4 +1,5 @@
 #include <opencv2/gpu/gpu.hpp>
+#include <opencv2/softcascade/softcascade.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <iostream>
 
@@ -46,7 +47,7 @@ int main(int argc, char** argv)
     float maxScale =  parser.get<float>("max_scale");
     int scales     =  parser.get<int>("total_scales");
 
-    using cv::gpu::SCascade;
+    using cv::softcascade::SCascade;
     SCascade cascade(minScale, maxScale, scales);
 
     if (!cascade.load(fs.getFirstTopLevelNode()))
@@ -79,7 +80,7 @@ int main(int argc, char** argv)
         cascade.detect(dframe, roi, objects);
 
         cv::Mat dt(objects);
-        typedef cv::gpu::SCascade::Detection Detection;
+        typedef cv::softcascade::SCascade::Detection Detection;
 
         Detection* dts = ((Detection*)dt.data) + 1;
         int* count = dt.ptr<int>(0);