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/dnn/test/test_main.cpp

@@ -11,7 +11,7 @@ CV_TEST_MAIN("",
     extraTestDataPath ? (void)cvtest::addDataSearchPath(extraTestDataPath) : (void)0
 )
 
-namespace cvtest
+namespace opencv_test
 {
 
 using namespace cv;