More fixes, translated remaining string

As indicated by AaronVanGeffen.

I quickly walked trough the entire file, fixing some translations, including a few for consistency, and a few to prevent overflowing. Also translated what _seemed_ like the only remaining untranslated string! (Not counting strings that are currently untranslatable.) In other words, it means dutch.txt is as complete as it can currently get.

@AaronVanGeffen: could you take a look as well and tell if you can find any errors?
Maybe you could also just write the following?: Neem klusjesman aan, Neem monteur aan, Neem bewaker (originally translated to Veiligheidsagent in RCT2, but it is indeedly a bit too long) aan en Neem entertainer aan. This is also how it was in the original Dutch translation of RCT2. I'm a native Dutch speaker too, would you mind if I would try to help you with the Dutch translation?; like fixing some things or/and making some improvements. :)