Fixed inversion of ymin and ymax in detection models output

[fantes]

FIX #674

• ymin and ymax were previoulsy swapped, ie ymin was > ymax

• this patch correctly set ymin and ymax so that it respects caffe detection_ouput layer semantics as for instance in https://github.com/jolibrain/caffe/blob/master/src/caffe/layers/detection_output_layer.cpp#L368

• when using output of detection models, if ymin and ymax are used as is, then problems are to be exepcted, but if they are used with somthing like height = abs(ymin-ymax) , then this patch will not change anything.

[beniz]

Thanks. Beware I believe this PR may break image cropping in chains, especially this line: https://github.com/jolibrain/deepdetect/blob/master/src/chain_actions.cc#L91

Maybe update the PR so that it becomes:

cv::Rect roi(cxmin,cymax,cxmax-cxmin,cymax-cymin);

[beniz]

Also, this line may need to be modified, https://github.com/jolibrain/deepdetect/blob/master/src/chain_actions.cc#L89

[fantes]

Thanks. Beware I believe this PR may break image cropping in chains, especially this line: https://github.com/jolibrain/deepdetect/blob/master/src/chain_actions.cc#L91

Maybe update the PR so that it becomes:

cv::Rect roi(cxmin,cymax,cxmax-cxmin,cymax-cymin);

done

[fantes]

Thanks. Beware I believe this PR may break image cropping in chains, especially this line: https://github.com/jolibrain/deepdetect/blob/master/src/chain_actions.cc#L91

Maybe update the PR so that it becomes:

cv::Rect roi(cxmin,cymax,cxmax-cxmin,cymax-cymin);

done