Bug: org-table-import fails to import xlxs files

[swedebugia <swedebugia@riseup.net>]

Hi

Thanks for a making this fantastic program!

I think I found a bug.

When trying to import a xslx table into org-mode I get a lot of binary
data instead of a table back.

I would rather either get an error saying it is not supported yet or an
org-table.

Recoll supports xlsx files it seems, so it should be possible
with python 3 at least to make this work also in org-mode. See
https://www.lesbonscomptes.com/recoll/pages/features.html

I found this in Arch:
$ pacman -Ss xlsx
community/python-openpyxl 3.0.5-1
    A Python library to read/write Excel 2007 xlsx/xlsm files

Other ones written in python:
https://github.com/dilshod/xlsx2csv (not that active)
https://github.com/wireservice/csvkit (active)

Also gnumeric can convert it:
The Gnumeric spreadsheet application comes with a command line utility
called ssconvert that can convert between a variety of spreadsheet
formats:

$ ssconvert Book1.xlsx newfile.csv
Unfortunately it is only available with the gnumeric GUI currently
which is ~14MB bloat. 
See
http://stackoverflow.com/questions/10557360/ddg#10580741
Source here https://gitlab.gnome.org/GNOME/gnumeric (active)

Cheers
swedebugia