Emacs-Guix released outside from Guix

[Alex Kost]

Hello, I've been working on Emacs interface outside from the Guix repo
for some time, I mean I'm not going to maintain it inside Guix, sorry :-(

The main reason, is, well, inconvenience for me: I don't like to bother
people with patches, etc.  I tried to explain it at
<http://lists.gnu.org/archive/html/guix-devel/2016-07/msg01091.html>.
There are 2 more reasons above that:

- I'd like to make it available on MELPA (people asked about it several
  times in the past);

- Currently, to be able to use it on non-GuixSD system, a user has to
  install 'guix' package into their profile.  This has never looked good
  to me (installing a whole guix only for a small part of it). I would
  prefer to make "guix package -i emacs-guix" possible instead.

So I'd like to add 'emacs-guix' package (the current patchset) and to
remove it from the Guix source tree, if you don't mind.

The code of Emacs-Guix can be found on github¹ or notabug².  I've just
made a release (v0.2); and I'm going to send a message with the summary
of changes later.

¹ https://github.com/alezost/guix.el
² https://notabug.org/alezost/emacs-guix

I'm also sending the following patches:

[PATCH 1/2] gnu: Add emacs-bui.
[PATCH 2/2] gnu: Add emacs-guix.