Added Dutch language

Hi Mattt,

I added the Dutch language to the project and added a future deictic expression, because in Dutch we have specific words for 'the day after tomorrow' and 'the day before yesterday'.

I also recreated the demo project file, because it was corrupted and I couldn't find out what was wrong with it. I don't know if you want to merge this commit, because I saw you also made some changes on the project file, but I couldn't find an option in Guthub to make a pull request for a specific commit.

Regards, André