postfix-2.12-20140530
Ignore more compiler artifacts
postfix-2.12-20140531
Disable export and low grade ciphers

Set the default opportunistic cipher grade to "medium" in the SMTP server
and client.  Also set the underlying TLS library cipher grade definitions
of "export" and "low" to exclude EXPORT and LOW ciphers, making these
equivalent to "medium".

Document the changes.