po: Copied missing nl.po translation from the 2.0 branch.
* po/nl.po: Copy from 2.0 branch.
It's not clear to me why this didn't get transferred in
329ece46bf83871f01eb833d5ebec6da36bfcce0.
- Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>