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/imgproc/test/test_histograms.cpp

@@ -41,8 +41,7 @@
 
 #include "test_precomp.hpp"
 
-using namespace cv;
-using namespace std;
+namespace opencv_test { namespace {
 
 class CV_BaseHistTest : public cvtest::BaseTest
 {
@@ -1919,4 +1918,5 @@ TEST(Imgproc_Hist_CalcBackProject, accuracy) { CV_CalcBackProjectTest test; test
 TEST(Imgproc_Hist_CalcBackProjectPatch, accuracy) { CV_CalcBackProjectPatchTest test; test.safe_run(); }
 TEST(Imgproc_Hist_BayesianProb, accuracy) { CV_BayesianProbTest test; test.safe_run(); }
 
+}} // namespace
 /* End Of File */