[OpenCV 2.2] using namespace std; in the .h body !! (Bug #846)

Hi,

There is a mistake in opencv 2.2, very tedious when working on big projects with many dependencies:
In the "opencv2/flann/" module, there are several files containing a using namespace std in the common body of the .h. This implies that when including cv.h, we get conflicts with other types.

I recommand to put the "using namespace std" inside the cv namespace. This doesn't implies any changes for you but a lot for people using OpenCV.

Example:

h30. ORIGINAL

#ifndef OPENCV_RESULTSET_H
#define OPENCV_RESULTSET_H

#include <algorithm>
#include <limits>
#include <vector>
#include "opencv2/flann/dist.h"

using namespace std;

namespace cvflann {
[...]

h30. FIXED

#ifndef OPENCV_RESULTSET_H
#define OPENCV_RESULTSET_H

#include <algorithm>
#include <limits>
#include <vector>
#include "opencv2/flann/dist.h"

namespace cvflann {

using namespace std;
[...]

Thank you in advance,
Eloi du Bois.