Merge branch 'master' into core-updates

Conflicts:
	Makefile.am
	gnu/packages/autotools.scm
	gnu/packages/guile.scm
	gnu/packages/python.scm
	gnu/packages/shishi.scm
	guix/gnu-maintenance.scm
	guix/scripts/build.scm
	guix/scripts/gc.scm
	guix/scripts/package.scm
	guix/scripts/substitute-binary.scm
	guix/ui.scm
	nix/nix-daemon/guix-daemon.cc
	test-env.in
	tests/nar.scm
	tests/store.scm

gnu: libgcrypt: Update to 1.5.2.

* gnu/packages/gnupg.scm (libgcrypt): Update to 1.5.2.

gnu: dejagnu: Update to 1.5.1.

* gnu/packages/dejagnu.scm (dejagnu): Update to 1.5.1.

gnu: nano: Update to 2.3.2.

* gnu/packages/nano.scm (nano): Update to 2.3.2.

gnu: ed: Update to 1.8.

* gnu/packages/ed.scm (ed): Update to 1.8.

gnu-maintenance: Add newline in warning messages.

* guix/gnu-maintenance.scm (download-tarball): Add newline in warning
  messages.

doc: Add note on installing Guix from Guix.

* README (Installing Guix from Guix): New section.
  Suggested by Alex Sassmannshausen <alex.sassmannshausen@gmail.com>.

refresh: Add `--select'.

* guix/scripts/refresh.scm (%options): Add `--select'.
  (show-help): Likewise.  Augment initial help text.
  (guix-refresh)[core-package?]: New procedure.
  Use it when selecting packages.

web: Factorize `http-get' hackery.

This should fix `substitute-binary --query' on Guile 2.0.5.

* guix/web.scm: New file.
* Makefile.am (MODULES): Add it.
* po/POTFILES.in: Add it.
* guix/gnu-maintenance.scm (http-fetch): Remove.
  (%package-list-url): Turn into a URI.
  (official-gnu-packages): Add #:text? #t to `http-fetch' call.
* guix/scripts/substitute-binary.scm (fetch): Remove `http' case, and
  use `http-fetch' instead.

gnu: wdiff: Update to 1.2.1.

* gnu/packages/wdiff.scm (wdiff): Update to 1.2.1.  Add Texinfo as an input.

gnu: nettle: Update to 2.7.

* gnu/packages/nettle.scm (nettle): Update to 2.7.

gnu: libtasn1: Update to 3.3.

* gnu/packages/gnutls.scm (libtasn1): Update to 3.3.

gnu-maintenance: Optimize `gnu-package?'.

* guix/gnu-maintenance.scm (gnu-package?): Capture a memoizing version
  of `gnu-package?'.

gnu-maintenance: Optimize `release-file'.

* guix/gnu-maintenance.scm (tarball-regexp): Remove.
  (%tarball-rx): New variable.
  (release-file): Adjust to use %TARBALL-RX.

gnu-maintenance: Optimize `latest-release'.

* guix/gnu-maintenance.scm (tarball-regexp, sans-extension,
  release-file): New procedures.
  (%alpha-tarball-rx): New variable.
  (releases): Use them instead of local copies.
  (latest-release): Rewrite to not do a recursive search of all
  versions and instead jump directly to the latest.

Add `guix refresh' and related auto-update tools.

* guix/gnu-maintenance.scm (ftp-server/directory)[quirks]: Add glib.
  (package-update-path, download-tarball, package-update,
  update-package-source): New procedures.
* guix/gnupg.scm, guix/scripts/refresh.scm: New files.
* Makefile.am (MODULES): Add them.
* guix/utils.scm (file-extension): New procedure.

packages: Use `read' and source properties for `package-field-location'.

* guix/packages.scm (package-field-location): Rewrite using `read' and
  source properties.  Change to return #f upon failure.
* tests/packages.scm ("package-field-location"): Check for #f upon failure.
* build-aux/sync-synopses.scm: Adjust accordingly.

utils: Fix column number returned by `source-properties->location'.

* guix/utils.scm (source-properties->location): Use COL, not COL + 1.

gnu: hop: Update hash to match hop-2.4.0.tar.gz, which was modified in place.

* gnu/packages/scheme.scm (hop): Update the hash.

packages: Add `package-field-location'.

* guix/packages.scm (package-field-location): New procedure.
* build-aux/sync-synopses.scm: Use it instead of `package-location'.
* tests/packages.scm ("package-field-location"): New test.