parsing CSV file with 2 empty newlines at end fails

[Vindaar]

If there's two empty newlines at the end (so one fully empty line), our CSV parser chokes.

It's a bit difficult, as either we need to check for this in the first line counting pass (slows it down) or reduce the size of the final tensor afterwards. Need to think about the most elegant solution.

To reproduce just take a working CSV file and 2 newlines at the end and run.

[Vindaar]

This can partially be handled now by using the maxLines option added in #46. Still this particular case should be handled automatically.