[REVEIW 3-6] fix import/export of column widths fdo#55623

[Noel Power]

It seems that when both importing and exporting xlsx column widths were 
mishandled, so on import the wrong column width was calculated. To make 
things worse when exporting the conversion used strange ( hardcoded 
fudge ) calculation. So not only ( even when using same or metrically 
equiv fonts ) would the export fail to give the correct result to excel 
even when reading back the exported document the column widths would be 
different ( and smaller ) Hehe if you were patient enough to do enough 
modify/saves with an xlsx document you probably could make your column 
widths shrink to practically nothing

please think about cherry-picking 
http://cgit.freedesktop.org/libreoffice/core/commit/?id=8e753f8446554822d97969b0c18eba6cb9d79e26


Noel