Fix miscellaneous typos in comments

sed s/supress/suppress/g
sed s/depencies/dependencies/g

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Mail:

* Updated Roundcube to version 1.1.3.
* Auto-create aliases for abuse@, as required by RFC2142.
* The DANE TLSA record is changed to use the certificate subject public key rather than the whole certificate, which means the record remains valid after certificate changes (so long as the private key remains the same, which it does for us).

Control panel:

* When IPv6 is enabled, check that system services are accessible over IPv6 too, that the box's hostname resolves over IPv6, and that reverse DNS is setup correctly for IPv6.
* Explanatory text for setting up secondary nameserver is added/fixed.
* DNS checks now have a timeout in case a DNS server is not responding, so the checks don't stall indefinitely.
* Better messages if external DNS is used and, weirdly, custom secondary nameservers are set.
* Add POP to the mail client settings documentation.
* The box's IP address is added to the fail2ban whitelist so that the status checks don't trigger the machine banning itself, which results in the status checks showing services down even though they are running.
* For SSL certificates, rather than asking you what country you are in during setup, ask at the time a CSR is generated. The default system self-signed certificate now omits a country in the subject (it was never needed). The CSR_COUNTRY Mail-in-a-Box setting is dropped entirely.

System:

* Nightly backups and system status checks are now moved to 3am in the system's timezone.
* fail2ban's recidive jail is now active, which guards against persistent brute force login attacks over long periods of time.
* Setup (first run only) now asks for your timezone to set the system time.
* The Exchange/ActiveSync server is now taken offline during nightly backups (along with SMTP and IMAP).
* The machine's random number generator (/dev/urandom) is now seeded with Ubuntu Pollinate and a blocking read on /dev/random.
* DNSSEC key generation during install now uses /dev/urandom (instead of /dev/random), which is faster.
* The $STORAGE_ROOT/ssl directory is flattened by a migration script and the system SSL certificate path is now a symlink to the actual certificate.
* If ownCloud sends out email, it will use the box's administrative address now (admin@yourboxname).
* Z-Push (Exchange/ActiveSync) logs now exclude warnings and are now rotated to save disk space.
* Fix pip command that might have not installed all necessary Python packages.
* The control panel and backup would not work on Google Compute Engine because GCE installs a conflicting boto package.
* Added a new command `management/backup.py --restore` to restore files from a backup to a target directory (command line arguments are passed to `duplicity restore`).

Allow remote client for Sieve

change DANE TLSA record to hash the subject public key rather than the whole certificate, which means it is good for any certificate tied to the same private key

Better for short-lived certificates. This is especially in preparation to using certificates from Let's Encrypt.

see #268

previously these were run in a cron.daily script which per crontab is run at 6:25 am local time

clean up the backup time patch: dont choose timezone here, move status checks into the same 3am script

closes #294
see #328
maybe related to #235

tiny tweaks to make the bash docs slightly more readable

Activate FAIL2BAN recidive jail

Add alias for abuse@

don't install bind9-host when setting hostname

also remove an incorrect comment

fail2ban: whitelist our machine's public ip address so status checks dont cause bans of the machine itself

make the system SSL certificate a symlink so we never have to replace a certificate file, and flatten the directory structure of user-installed certificates