doc: Regenerate 'guix graph' examples.

* doc/images/coreutils-bag-graph.dot, doc/images/coreutils-graph.dot:
  Regenerate from current packages.  This removes the weird dependency
  on 'sed'.

gnu: Add python-libarchive-c.

* gnu/packages/python.scm (python-libarchive-c, python2-libarchive-c):
  New variables.

gnu: Add python-tlsh.

* gnu/packages/python.scm (python-tlsh, python2-tlsh): New variable.

gnu: Add ruby-yard.

* gnu/packages/ruby.scm (ruby-yard): New variable.

gnu: Add ruby-rspec-2.

* gnu/packages/ruby.scm (ruby-rspec-2): New variable.

gnu: Add ruby-rspec-mocks-2.

* gnu/packages/ruby.scm (ruby-rspec-mocks-2): New variable.

gnu: Add ruby-rspec-expectations-2.

* gnu/packages/ruby.scm (ruby-rspec-expectations-2): New variable.

gnu: Add ruby-rspec-core-2.

* gnu/packages/ruby.scm (ruby-rspec-core-2): New variable.

gnu: python-scipy: Add phase to fix tests.

* gnu/packages/python.scm (python-scipy)[arguments]: Add build phase
  "fix-tests".

gnu: python-scipy: Add numpydoc to native-inputs.

* gnu/packages/python.scm (python-numpydoc)[native-inputs]: Add
  python-numpydoc.

services: Unmount user file systems after process termination.

* gnu/services/base.scm (user-unmount-service-type): Change label and
  dmd name to 'user-file-systems'.
  (user-processes-service-type)[requirement]: Add 'user-file-systems'.

guix system: Add 'dmd-graph' command.

* guix/scripts/system.scm (dmd-service-node-label,
  dmd-service-node-type, export-dmd-graph): New procedures.
  (show-help): Add 'dmd-graph'.
  (guix-system)[parse-sub-command]: Likewise.
  Honor it.
* doc/guix.texi (Invoking guix system): Document it.
  (dmd Services): Add an illustration and explanation.
* doc/images/dmd-graph.dot: New file.
* doc.am (DOT_FILES): Add it.

services: Add 'dmd-service-back-edges'.

* gnu/services/dmd.scm (dmd-service-back-edges): New procedure.
* tests/services.scm ("dmd-service-back-edges"): New test.

services: Prefix <dmd-service> accessors with 'dmd-'.

* gnu/services/dmd.scm (<dmd-service>): Prefix accessor identifiers with
  'dmd-', as was intended.  Update users accordingly.

guix system: Add 'extension-graph' command.

* guix/scripts/system.scm (service-node-label, service-node-type,
  export-extension-graph): New procedures.
  (guix-system)[parse-sub-command]: Add 'extension-graph'.
  Honor it.
  (show-help): Add 'extension-graph'.
* doc/guix.texi (Invoking guix system): Document it.
  (Service Composition): Add cross-reference.

graph: 'export-graph' takes a #:reverse-edges? parameter.

* guix/scripts/graph.scm (export-graph): Add #:reverse-edges? parameter
  and honor it.

services: 'dmd-service-type' takes a service name.

* gnu/services/dmd.scm (dmd-service-type): Add 'service-name'
  parameter.
* gnu/services/base.scm, gnu/services/networking.scm,
  gnu/system/install.scm: Adjust callers.

services: Export 'service-back-edges'.

* gnu/services.scm: Export 'service-back-edges' and <service-type>
  accessors.
* tests/services.scm ("service-back-edges"): New test.

build-system/gnu: dist-package: Use 'autoconf-wrapper'.

* guix/build-system/gnu.scm (dist-package): Use AUTOCONF-WRAPPER instead
  of AUTOCONF.

hydra: Add Graphviz and help2man as inputs to the Guix job set.

* build-aux/hydra/guix.scm (tarball-package): Add GRAPHVIZ and HELP2MAN
  to 'native-inputs' of GUIX.