ts: refactor OpenCV tests

- removed tr1 usage (dropped in C++17)
- moved includes of vector/map/iostream/limits into ts.hpp
- require opencv_test + anonymous namespace (added compile check)
- fixed norm() usage (must be from cvtest::norm for checks) and other conflict functions
- added missing license headers

modules/features2d/test/test_keypoints.cpp

@@ -42,8 +42,7 @@
 #include "test_precomp.hpp"
 #include "opencv2/core/core_c.h"
 
-using namespace std;
-using namespace cv;
+namespace opencv_test { namespace {
 
 const string FEATURES2D_DIR = "features2d";
 const string IMAGE_FILENAME = "tsukuba.png";
@@ -177,3 +176,5 @@ TEST(Features2d_Detector_Keypoints_AKAZE, validation)
     CV_FeatureDetectorKeypointsTest test_mldb(AKAZE::create(AKAZE::DESCRIPTOR_MLDB));
     test_mldb.safe_run();
 }
+
+}} // namespace