FreeXL: bugs in FreeXL-2.0.0 cannot open multiple columns data files

[Shun Wang]

Hi,

 thanks for your work!

I cannot open the big .xlsx files with multiple columns(more than 725 I guess).to reproduce:

1. creat a .xlsx file with 725 columns;
2. build the freexl 2.0.0
3. try open that file.

It may because the `find_col_no function` can olny find max col as "ZZ" with two alphabet? I can reproduce it also on Linux and Windows. I also made an issue report at: FreeXL

cheers.

Shun Wang