std::map loop using for is wrong in GetMeanIntensity() when dealing wth labelimage which contains non contiguous labels. Mantis #ref564

BUG: OGRDataSourceWrapper::GetProjectionRef() does not actually return the projection ref, this property is owned by each layer

now compliant with ouptput parameters behaviour (commit from the 4th of June). Not sure it is the best solution. Ity allows to keep baselines
related to ReadImageInfo application like this

ENH: MeanShiftSegmentation application, which duplicates Segmentation application has been changed to MeanShiftSmoothing application.