message: photo: Decolor corrections
  * Keep image aspect ratio in resize called in grad_system and
  weak_order
  * Bug correction in loop inside Decolor::gradvector
diff: @@ -159,12 +159,12 @@ void Decolor::gradvector(const Mat &img, vector <double> &grad) const
  for(int i=0;i<height;i++)
  for(int j=0;j<width;j++)
  - grad[i*height + j] = d_trans.at<float>(i, j);
  + grad[i*width + j] = d_trans.at<float>(i, j);
  const int offset = width * height;
  for(int i=0;i<height;i++)
  for(int j=0;j<width;j++)
  - grad[offset + i * height + j] = d1_trans.at<float>(i, j);
  + grad[offset + i * width + j] = d1_trans.at<float>(i, j);
  }
  void Decolor::colorGrad(const Mat &img, vector <double> &Cg) const
  @@ -212,7 +212,7 @@ void Decolor::weak_order(const Mat &im, vector <double> &alf) const
  if((h + w) > 800)
  {
  const double sizefactor = double(800)/(h+w);
  - resize(im, img, Size(cvRound(h*sizefactor), cvRound(w*sizefactor)));
  + resize(im, img, Size(cvRound(w*sizefactor), cvRound(h*sizefactor)));
  }
  else
  {
  @@ -260,7 +260,7 @@ void Decolor::grad_system(const Mat &im, vector < vector < double > > &polyGrad,
  if((h + w) > 800)
  {
  const double sizefactor = double(800)/(h+w);
  - resize(im, img, Size(cvRound(h*sizefactor), cvRound(w*sizefactor)));
  + resize(im, img, Size(cvRound(w*sizefactor), cvRound(h*sizefactor)));
  }
  else
  {
  