Remove all using directives for STL namespace and members

Made all STL usages explicit to be able automatically find all usages of
particular class or function.

modules/calib3d/test/test_cameracalibration.cpp

@@ -43,6 +43,9 @@
 
 #include <limits>
 
+using namespace std;
+using namespace cv;
+
 #if 0
 class CV_ProjectPointsTest : public cvtest::ArrayTest
 {
@@ -241,8 +244,6 @@ CV_ProjectPointsTest ProjectPoints_test;
 
 #endif
 
-using namespace cv;
-
 // --------------------------------- CV_CameraCalibrationTest --------------------------------------------
 
 class CV_CameraCalibrationTest : public cvtest::BaseTest