"make FontForge.pot" like in htdocs/uitranslationnotes.html

Allow users to create new language po files based on info shown here.
Update de.po using "make FontForge.pot"

Most of this de.po updating is related to "[Fontforge-devel] UI language"
Go see http://sourceforge.net/mailarchive/message.php?msg_id=31675268

Kept the same copyright messages since none of this update is "language".