import: cran: Parse DESCRIPTION instead of HTML.

* guix/import/cran.scm (description->alist, listify,
  beautify-description, description->package): New procedures.
(table-datum, downloads->url, nodes->text, cran-sxml->sexp): Remove
proceduces.
(latest-release): Use parsed DESCRIPTION instead of SXML.
* tests/cran.scm: Rewrite to match importer.

import: cran: Match more license strings.

* guix/import/cran.scm (string->license): Match more license strings to
  license symbols.

import: pypi: Updater silently ignores packages without source.

Reported by Andreas Enge <andreas@enge.fr>
at <https://lists.gnu.org/archive/html/guix-devel/2015-11/msg00764.html>.

* guix/import/pypi.scm (&missing-source-error): New error type.
(latest-source-release): Raise it instead of using 'error'.
(pypi->guix-package): Guard against it and use 'leave' to report the
error.
(latest-release): Guard against it and return #f when caught.

import: hackage: Handle CRLF end of line style.

* guix/import/hackage.scm (hackage-fetch, hackage->guix-package): Use
  'canonical-newline-port'.

import: hackage: Make parsing of tests and fields more flexible.

* guix/import/cabal.scm (is-test): Allow spaces between keyword and
  parentheses.
  (is-id): Add argument 'port'.  Allow spaces between keyword and column.
  (lex-word): Adjust call to 'is-id'.

import: hackage: Make it resilient to missing final newline.

* guix/import/cabal.scm (peek-next-line-indent): Check for missing final
  newline.

import: hackage: Imporve parsing of tests.

* guix/import/cabal.scm (lex-word): Add support for tests with no spaces.
  (impl): Rewrite.

import: hackage: Add recognition of 'true' and 'false' symbols.

* guix/import/cabal.scm (is-true, is-false, lex-true, lex-false): New procedures.
  (lex-word): Use them.
  (make-cabal-parser): Add TRUE and FALSE tokens.
  (eval): Add entries for 'true and 'false symbols.

import: pypi: Make downloads silent.

* guix/import/pypi.scm (pypi-fetch): Wrap body in
  'call-with-output-file' and 'with-error-to-port'.

import: pypi: Add missing copyright line.

* guix/import/pypi.scm: Add missing copyright line for bab020d.

import: pypi: add updater

* guix/import/pypi.scm (guix-package->pypi-name,
  latest-release): New procedures.
  (%pypi-updater): New variable.
* guix/scripts/refresh.scm (%updaters): Add %PYPI-UPDATER.
* doc/guix.texi (Invoking guix refresh): Mention PyPI

import: pypi: Use "pypi-uri" instead of building the URL manually.

* guix/import/pypi.scm (make-pypi-sexp): Use "pypi-uri".
* tests/pypi.scm: Update the tests accordingly.

import: gnu: Update to the (guix upstream) API.

This is a followup to 0a7c5a0.

* guix/import/gnu.scm (preferred-archive-type): Use
  'upstream-source-archive-types' instead of 'gnu-release-archive-types'.
  (gnu-package->sexp): Use 'upstream-source-urls' et al.  Update call to
  'download-tarball'.
  (gnu->guix-package): Use <upstream-source> instead of <gnu-release>.
* guix/upstream.scm (upstream-source-archive-types): Export.

Merge branch 'master' into dbus-update

upstream: Add 'description' field to 'upstream-updater'.

Suggested by Ludovic Courtès <ludo@gnu.org>.

* guix/upstream.scm (<upstream-updater>): Use 'define-record-type*'.
  [description]: New field.
  (lookup-updater): Adjust accordingly.
* guix/gnu-maintenance.scm (%gnu-updater): Likewise.
* guix/import/cran.scm (%cran-updater): Likewise.
* guix/import/elpa.scm (%elpa-updater): Likewise.
* po/guix/POTFILES.in: Add guix/scripts/import/cran.scm and
  guix/gnu-maintenance.scm.

Merge branch 'master' into dbus-update

import: hackage: Update GHC libraries for 7.10.2.

Update ghc-standard-libraries to match the output of `ghc-pkg list` when
using GHC 7.10.2.

* guix/import/hackage.scm (ghc-standard-libraries): Sort and update list
  of core GHC libraries.

import: cran: Add copyright notice.

Add notice for commit d882c23.

import: cran: Avoid HTTP redirect.

* guix/import/cran.scm (cran-fetch): Add trailing slash in URL to avoid
  HTTP redirect.

import: cran: Add updater.

* guix/import/cran.scm (downloads->url, nodes->text): New procedures.
  (cran-sxml->sexp): Use them.  Remove equivalent local code.
  (latest-release, cran-package?): New procedures.
  (%cran-updater): New variable.
* guix/scripts/refresh.scm (%updaters): Add %CRAN-UPDATER.
* doc/guix.texi (Invoking guix refresh): Mention CRAN.