Support for `worksheet_add_table`

[Michoels]

First off, thank for the great lib!

I'm trying to use this library's FFI bindings to use the worksheet_add_table function. It's documented in the Libxlsxwriter docs here.

I tried using this:

Libxlsxwriter.worksheet_add_table

But got:

undefined method `worksheet_add_table' for module Libxlsxwriter

I dug through the docs, and it appears that none of the Libxlsxwriter table functions have been bound. Am I missing something, or is it officially not supported?