Translations Makefile.am fix

`Makefile.am` in the `translations/` directory has been updated to be able to correctly find the `qucs/` sources and to put the generated `.ts` files in the right directory. While I was at it, the translations have been regenerated so that `linguist` can again correctly cross-reference the sources when showing the translations text.

A couple of additional questions:
- is the copyright notice in `Makefile.am` correct?
- I agree that it's better to have the translation files in their own directory, but why are they in `/qucs/qucs/translations` and not in `qucs/translations`, since they contain the strings for all the applications and not only the GUI ?