Add Dutch localization

[josgrp]

I would like to contribute to the localization for the Dutch language.
On the site it reads that I should contact a project maintainer.
I started with copying the spreadsheet and asking the owner of the Google docs spreadsheet for access.

[inexorabletash]

I'll get in touch, thanks!

[inexorabletash]

Resolved by 5c7695e (I just messed up the magic incantation)