Review the operator Median. Should we create an MEDSTK?

[raphaelrpl]

The operator MEDIAN consists in stack all images that are clear_data and mark the not_clear_data as masked array. After that apply a median over only clear_data data. When there is no value for any pixel, the nodata is required.

Should we use best pixel image when no any clear data for Median? Create a new operator: MEDSTK?