to mitigate POODLE vulnerability

Postfix: Disable SSLv2 and SSLv3 for 'mandatory SSL' mode connections to completely mitigate the POODLE issue.

Resolves #114

http://ahbl.org/content/changes-ahbl

Fixes #232

This prevents timeouts when trying to sync very large mailboxes. By
default, z-push attempts to get headers for all messages in a folder.

I had a # in my mail_db_password and spent the last 2 hours trying to figure out why I couldn't connect by IMAP. A # is only allowed if the connect string is wrapped in quotes.

Fixes issue #8. Adds new variable mail_header_privacy, on by default.
Installs postfix-pcre unconditionally, and then copies the pcre file
over and adds the header check to main.cf based on the variable value.
“this header replacement works great, but it logs that the replacement
has been done, which means that you are storing this information,
unless you are anonymizing your logs”

PostgreSQL works similarly with varchar and text columns. Rather than
limiting the amount of characters a column can hold simply use text
columns.

Because this sql is now PostgreSQL specific, there's no need to maintain
what was set in the mysql settings.

Remove all configuration for MySQL and configure PostgreSQL as the main
database.

All *_mysql_* options have been changed to *_db_* options.

Postgres requires the database user to have a password in order to
connect via localhost. The db_admin_password option is used to set the
password of the admin user (usually postgres).

When you're hosting a couple of hundred aliases, you will benefit.
It seems safer to create the index and deal with the slight overhead
for just a couple of records, as opposed to not having these
indexes and deal with serious performance issues if you have
lots of aliases on the machine.

Signed-off-by: PajamaSoft <support@pajamasoft.com>

Use the changed `mail_virtual_users` structure to ensure directories and
sieve rules are created for each defined account.

These are the changes necessary to enable Roundcube's manage sieve plugin to mange server-side sieve filters.

Signed-off-by: PajamaSoft <support@pajamasoft.com>

Added friendly_networks variable to denote whitelisted networks

(such as root's cron errors)

Fix CAcert usage in postfix and dovecot

Fix Postfix configuration file to link to correct SSL certificate locations

Thanks @pjan