[exim] EBL: blacklist for email addresses in Reply-To and me…

The purpose of the EBL blacklist is described on
http://msbl.org/ebl-purpose.htm

I tested EBL since October 2016, today it was declared in public beta:
https://spammers.dontlike.us/mailman/private/list/2017-June/010493.html

> The Email Blocklist has entered Beta 2, and is now open for testing by
> the public. If you have not tried the list out, please do so. We would
> love to receive your feedback, and think you will like seeing less 419
> Advance Fee Fraud and some other types of spam in your inboxes.
>
> You can find information, instructions, and tools on the website:
> http://msbl.org/ebl-implementation.html

How to use EBL in Exim config (requires Exim version 4.87 or higher):
https://github.com/Exim/exim/wiki/EBL