Small fix to impute text
Added an option to output csv directly from qu3d(init) if further manipulations are not needed
Changed jpeg quality to 75 in impute_text.py
Upd impute text for jpg
Added check for number of groups in convert to csv
Changed qu3d to output empty file for empty mask and fixed other operators to accept empty mask
Changed sselect to use modified lister coded as the lister for 3d
Changed sselect and sselect3d to check only size with negative eps