The summary of the long weekend, very funny tool already, Excel (xls, xlsx) and Open/LibreOffice (ods) loading works nicely, 
it already draws right, left and center aligned, with background and colors, also the calculation works as it should be and 
I implemented the multiple Worksheets selector. It’s much faster now, because it only redraws the cells which were changed 
(especially when dragging the cell border or selecting cells)
So I made a little “Release”, it’s just everything hammered together, still VERY buggy! for sure. just call “Leu <your file>” 
if you call without a file you get an empty playground where you can type your own stuff into, but formats and so on are 
not available.

Have fun!
Marcus 'ALB42' Sackrow