Integration of Gossie contribution

From Gossie :

Okay, I have now used the tool and checked every string in there for 3
languages: English, German and Dutch. Phew! Four hours of work!

Some of the original translations were quite strange  I also corrected
inconsistencies in the use of button labels throughout the application
(like 'previous', 'next' and 'close'). If the next version incorporates
music, I don't think you should refer to the media files as 'video
files'. I tried to take those references out and replaced them with
'files' or 'media files'.

I did not change the text in the wizard as much this time  - in my
previous version I did not change the meaning, I only made it friendlier
(in the last screen I put some 'what to do next', those extra lines are
not in this version). Of course, you couldn't check this in Dutch. Sorry
about that!

So here's all the XML files back, as one zip file. Hopefully you will
incorporate this into the next release.