doc: Stylistic changes to "Packaging Guidelines"

doc: Add note about .dir-locals.el.

* HACKING (Coding Style): Mention special indentation rules and
  .dir-locals.el.

doc: Add a "Coding Style" section in 'HACKING'.

* HACKING (Coding Style): New section.

doc: Remove "Adding new packages" from `HACKING'.

* HACKING (Adding new packages): Remove since it's now in the manual.

doc: Remove an extra space after @ref.

gnu: hop: Allow compilation with Bigloo 4.0b.

Fixes <http://bugs.gnu.org/15194>.
Reported by Mark H Weaver <mhw@netris.org>.

* gnu/packages/patches/hop-bigloo-4.0b.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/scheme.scm (hop): Use it.

doc: Add duplicate copyright notice again.

* doc/guix.texi: Add second copyright notice again inside @ifinfo, needed
  since the first one does not appear in the info output.
  Partially undoes commit da7cabd.

doc: Fix the image size in PDF/PS/DVI output.

* doc/guix.texi (Bootstrapping): Specify an image width for the TeX
  output.  Before that, the image would be much wider than the US Letter
  page width.

build: Have `pdf' depend on the PDF image.

* doc.am (DOT_OPTIONS): Remove `-Tpng'.
  (.dot.pdf): New rule.
  (pdf-local): Depend on the .pdf.

build: Use `missing' for `dot'.

* configure.ac: Substitute `DOT'.
* doc.am (.dot.png, .dot.eps): Use $(DOT).

build: Build docs from the top-level Makefile.

This undoes commit 575ed8d ("doc: Create own Makefile.am in subdirectory."),
and fixes a bug whereby "make pdf" or "make ps" wouldn't do anything.

* doc/Makefile.am: Remove.
* doc.am: New file.  Use `-local' rules to build the image.
* Makefile.am: Include it.
* configure.ac: Use `-Woverride' to avoid undesired overridding of
  Automake rules.

gnu: gsl: Move from module algebra to maths.

* gnu/packages/algebra.scm (gsl): Move variable from here...
* gnu/packages/maths.scm (gsl): ...to here.

gnu: linux-initrd: Add (guix build linux-initrd) and use it.

* gnu/packages/linux-initrd.scm (qemu-initrd): Add #:modules argument.
  Factorize and move some of the code to...
* guix/build/linux-initrd.scm: ... here.  New file.
* Makefile.am (MODULES): Add it.

gnu: make-bootstrap: Remove the `debug' output from the static Coreutils.

* gnu/packages/make-bootstrap.scm (%static-inputs)[coreutils]: Add
  `outputs' field.

gnu: linux-initrd: Allow Guile modules to be embedded in the initrd.

* gnu/packages/linux-initrd.scm (raw-build-system): New macro.
  (module-package, compiled-module-package): New procedures.
  (expression->initrd): Add `modules' keyword parameter.
  Add "modules" and "modules/compiled" inputs; copy them onto the
  initrd.
* guix/derivations.scm (imported-modules, compiled-modules): Publicize.

gnu: imagemagick: Update to 6.8.6-9.

* gnu/packages/imagemagick.scm (imagemagick): Update to 6.8.6-9.

doc: Add package guidelines for names and numbers.

* doc/guix.texi: Three new subsections.

doc: Shuffle some text around.

* doc/guix.texi: Drop duplicate copyright notice, start section
    "Packaging Guidelines" with existant text.

doc: Create own Makefile.am in subdirectory.

* doc/Makefile.am: New file.
* Makefile.am: Reference subdirectory doc.

list-packages: Tidy CSS in preparation for split into external file.

* build-aux/list-packages.scm (insert-css): Tidy CSS alignment etc.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>