German translation

Finally translated everything including the nibs to German
Merge pull request #136 from barijaona/german

German translation (cherry picked from pull request #135)
Completes the previous commit on extension correction.
Only keep a pair of public/private keys for DSA signing.

This key pair (vienna_private_key.pem / vienna_public_key.pem) is available to all project admins.
Merge pull request #134 from barijaona/build

Minor improvement to build process