[PATCH 0/6] emacs: Add interface for package locations.

[Alex Kost]

Hello, this patchset adds an Emacs interface for package locations,
which is very similar to the existing interface for licenses
(guix-licenses, guix-packages-by-license and guix-browse-license-url
commands).

The following commands are added:

- "M-x guix-locations": display a list of package locations (see
  the left part of the screenshot¹).

- "M-x guix-packages-by-location": display packages from a particular
  location.

- "M-x guix-find-location": move to a particular location.  It is the
  same as you can do with "M-x guix-edit" but instead of selecting a
  package name, you choose a location.

Also *Guix Package Info* buffer shows "Packages" buttons that can be
used to display packages by license and by location (see the right part
of the screenshot).

[PATCH 1/6] emacs: Add 'guix-packages-by-location' command.
[PATCH 2/6] emacs: Separate package location code.
[PATCH 3/6] emacs: Make 'guix-find-location' interactive.
[PATCH 4/6] doc: emacs: Add "Locations" section.
[PATCH 5/6] emacs: Add interface for package locations.
[PATCH 6/6] emacs: Add license/location "Packages" buttons to Info.

¹ http://i.imgur.com/PBmuxex.png