the `displayImage()` function doesn't work as desired

[Reza-Rajabi]

the displayImage() function in the utility.h module does not work as expected. For example if you take a row of the sample data (ex. X.row(10)) and get an image from it by calling to getImageFromModelRow() function and pass that image to the displayImage() function, it shows a white image. That's interesting because, if you print out the image data inside the displayImage() function, the correct values has been passed to it. Also this function works properly when we called it in this line. The problem might be missing data when passing cv::Mat objects back and force, and the solution might be adding some copy() or clone().

[Reza-Rajabi]

We have test scenario (case 2) that calls on display function. This is helpful to reproduce the issue.