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/perf/perf_caffe.cpp

@@ -34,8 +34,7 @@
 #include <iostream>
 #include <caffe/caffe.hpp>
 
-namespace cvtest
-{
+namespace opencv_test {
 
 static caffe::Net<float>* initNet(std::string proto, std::string weights)
 {
@@ -108,6 +107,5 @@ PERF_TEST(MobileNet_SSD, CaffePerfTest)
     SANITY_CHECK_NOTHING();
 }
 
-}  // namespace cvtest
-
+} // namespace
 #endif  // HAVE_CAFFE