[Shotwell] Shotwell translation

[Martin Weißhaupt]

Finally I found some time to contribute something to shotwell.
The last few weeks I've been a bit stressed out ;-)

Ingo has done an amazing job translating shotwell into german but there 
where some minor things that I changed.

I found 2 untranslated strings in the fullscreen mode of shotwell:
Pin the toolbar
Leave Fullscreen

I also noticed that the menu bar says "Rotate the photos right" even if 
one photo is selected.
This is not too bad tough.

Regards,
Martin Weißhaupt