added GPU bilateral filter + tests

added GPU non local means brute force filter + tests

modules/gpu/test/utility.hpp

@@ -74,6 +74,11 @@ cv::Mat readImage(const std::string& fileName, int flags = cv::IMREAD_COLOR);
 //! read image from testdata folder and convert it to specified type
 cv::Mat readImageType(const std::string& fname, int type);
 
+//////////////////////////////////////////////////////////////////////
+// Image dumping
+
+void dumpImage(const std::string& fileName, const cv::Mat& image);
+
 //////////////////////////////////////////////////////////////////////
 // Gpu devices