Fix Google Authenticator file generation

Added Google Authenticator 2FA logins

Modify sshd_config in place

reduce z-push logrotation to 5 versions

Set a ServerName for apache (fixes #187)

add z-push logrotation

Properly generate a PHP /etc/roundcube/debian-db.php file

Ignore carddav database errors

This now works fine in Vagrant 1.4.3, remove the workaround

Properly set the roundcube database password

Import carddav database schema

Upgrade znc from 1.0 to 1.2 (latest release)

Relocate tarsnap.key into /decrypted

Safer symlink creation and downloaded file removal

Install the carddav plugin so owncloud contacts can be used (fixes #154)

Some minor tweaks

This reverts commit 703d356492.

Fix URL of z-push download

Data loss will occur if backing up postgresql while it runs. A simple
fix is to stop it during the backup. I've moved the backup to early
morning to reduce possible downtime.

A better approach would be to use pg_dump.

The previous behaviour relied on managesieve copying over the
.dovecot.sieve file into the user's directory. I found this to be
particularly fragile. For instance, re-deploying roundcube without
dovecot could overwrite the .dovecot.sieve symlink and break
managesieve.

A better approach is to use the global sieve configuration that
roundcube provides and not mess with dovecot's files directly.