fix(ods): support consecutive repeated empty cells

[PrettyWood]

closes #455

Explanation

We had two files: single-empty.ods that worked fine and multi-empty.ods that didn't
Why? Because for single-empty.ods the XML behind it only has one empty with table:table-row table:number-rows-repeated="7" whereas multi-empty.ods has one empty, one with table:table-row table:number-rows-repeated="4" and then one with table:table-row table:number-rows-repeated="2"

The code didn't support consecutive empty lines. I tried to make as little change as possible but there might well be a better way

[alexander-beedie]

Nice one.

[archqt]

A new version 1.5.0-1 is available for me on Archlinux, and still the same it doesn't work.

[tafia]

Thanks!