[PATCH] v3 .. Add epic5 irc client

[ng0]

Changes since the last patch 
(https://lists.gnu.org/archive/html/guix-devel/2016-10/msg00549.html):

* removed gdbm
* changed openssl to libressl (inline commented why)
* explicitly pointed the config to the tls implementation
* checked multiple networks for functionality, all work but...
... tls does not work when round robin of irc networks kick in.
It might be a bug with epic5 -> ircd being used. For me this is functional,
and I will get in contact with upstream developers (if they aren't using
something like github or gitlab these days) to investigate this problem.
epic5 is known to be difficult to configure, so I would not rule out an
error on my side (not the package) in my client config.

[PATCH] gnu: Add epic5.