gnu: Some cleanup based on lint checkers.

* gnu/packages/admin.scm, gnu/packages/aidc.scm, gnu/packages/algebra.scm,
  gnu/packages/apr.scm, gnu/packages/avahi.scm, gnu/packages/backup.scm,
  gnu/packages/base.scm, gnu/packages/calcurse.scm, gnu/packages/cdrom.scm,
  gnu/packages/check.scm, gnu/packages/compression.scm, gnu/packages/cook.scm,
  gnu/packages/crypto.scm, gnu/packages/cryptsetup.scm, gnu/packages/curl.scm,
  gnu/packages/cyrus-sasl.scm, gnu/packages/databases.scm,
  gnu/packages/doxygen.scm, gnu/packages/dwm.scm, gnu/packages/elf.scm,
  gnu/packages/emacs.scm, gnu/packages/feh.scm, gnu/packages/file.scm,
  gnu/packages/fish.scm, gnu/packages/flex.scm, gnu/packages/fltk.scm,
  gnu/packages/fontutils.scm, gnu/packages/games.scm, gnu/packages/gcal.scm,
  gnu/packages/gcc.scm, gnu/packages/geeqie.scm, gnu/packages/ghostscript.scm,
  gnu/packages/gimp.scm, gnu/packages/gl.scm, gnu/packages/glib.scm,
  gnu/packages/gnome.scm, gnu/packages/gnunet.scm, gnu/packages/gnupg.scm,
  gnu/packages/gperf.scm, gnu/packages/grub.scm, gnu/packages/gsasl.scm,
  gnu/packages/gtk.scm, gnu/packages/guile-wm.scm, gnu/packages/guile.scm,
  gnu/packages/hurd.scm, gnu/packages/icu4c.scm, gnu/packages/image.scm,
  gnu/packages/imagemagick.scm, gnu/packages/irssi.scm, gnu/packages/kde.scm,
  gnu/packages/libdaemon.scm, gnu/packages/libevent.scm,
  gnu/packages/libidn.scm, gnu/packages/libusb.scm, gnu/packages/linux.scm,
  gnu/packages/lout.scm, gnu/packages/lsh.scm, gnu/packages/lsof.scm,
  gnu/packages/lua.scm, gnu/packages/maths.scm, gnu/packages/mcrypt.scm,
  gnu/packages/mp3.scm, gnu/packages/netpbm.scm, gnu/packages/noweb.scm,
  gnu/packages/ocaml.scm, gnu/packages/openssl.scm, gnu/packages/pcre.scm,
  gnu/packages/pdf.scm, gnu/packages/pkg-config.scm,
  gnu/packages/pretty-print.scm, gnu/packages/python.scm, gnu/packages/qt.scm,
  gnu/packages/rsync.scm, gnu/packages/scheme.scm, gnu/packages/scrot.scm,
  gnu/packages/sdl.scm, gnu/packages/skribilo.scm, gnu/packages/ssh.scm,
  gnu/packages/stalonetray.scm, gnu/packages/tcl.scm, gnu/packages/tcsh.scm,
  gnu/packages/telephony.scm, gnu/packages/texlive.scm, gnu/packages/tor.scm,
  gnu/packages/valgrind.scm, gnu/packages/version-control.scm,
  gnu/packages/vim.scm, gnu/packages/vpn.scm, gnu/packages/w3m.scm,
  gnu/packages/web.scm, gnu/packages/wordnet.scm, gnu/packages/xiph.scm,
  gnu/packages/xml.scm, gnu/packages/xorg.scm, gnu/packages/zile.scm,
  gnu/packages/zip.scm, gnu/packages/zsh.scm [synopsis, description]: Adjust
  according to lint checkers.
* gnu/packages/fltk.scm (fltk)[source]: Wrap long line in uri.
* /gnu/packages/xiph.scm (libogg, libtheora, vorbis-tools)[source]: Same.

distro: Rename (distro) to (gnu packages).

* distro.scm: Rename to...
* gnu/packages.scm: ... this.  Update all users accordingly.
* Makefile.am (MODULES): Adjust accordingly.
* po/POTFILES.in: Likewise.

distro: Change the module name space to (gnu ...).

* distro: Rename to...
* gnu: ... this.  Update module names accordingly.
* Makefile.am: Adjust accordingly.
* po/POTFILES.in: Likewise.
* distro.scm: Search for files under /gnu/packages instead of
  /distro/packages.
* gnu/packages/base.scm (ld-wrapper-boot3): Likewise.

Merge branch 'master' into core-updates

Conflicts:
	build-aux/download.scm
	distro/packages/autotools.scm
	distro/packages/base.scm
	distro/packages/bootstrap.scm
	distro/packages/lsh.scm
	distro/packages/make-bootstrap.scm
	distro/packages/ncurses.scm
	distro/packages/perl.scm
	tests/derivations.scm
	tests/union.scm

Update license headers.

Change all license headers, except guix/build/* and ld-wrapper.scm, with
this code:

  (use-modules (guix build utils)
	       (srfi srfi-1))

  (fluid-set! %default-port-encoding "UTF-8")

  (substitute* (remove (lambda (f)
			 (or (string-contains f ".tar.")
			     (string-contains f ".git/")
			     (string-contains f ".so")
			     (string-suffix? ".o" f)
			     (string-suffix? ".a" f)
			     (string-suffix? ".go" f)
			     (string-suffix? ".pdf" f)
			     (string-suffix? ".png" f)
			     (string-suffix? ".info" f)
			     (equal? (basename f) "guix-daemon")
			     (equal? (basename f) "nix-setuid-helper")
			     (string-contains f "nix-upstream/")
			     (string-contains f "distro/packages/bootstrap/")))
		       (find-files "." "\\.[a-z]+$"))
    (("^([[:graph:]]+) This file is part of Guix." _ comment-start)
     (string-append comment-start " This file is part of GNU Guix."))
    (("^([[:graph:]]+) Guix --- Nix package management.*" _ comment-start)
     (string-append comment-start
		    " GNU Guix --- Functional package management for GNU\n"))
    (("^([[:graph:]]+) Guix is " _ comment-start)
     (string-append comment-start " GNU Guix is "))
    (("^([[:graph:]]+) along with Guix." _ comment-start)
     (string-append comment-start " along with GNU Guix."))
    (("^([[:graph:]]+) Copyright \\(C\\)" _ comment-start)
     (string-append comment-start " Copyright ©")))

Change headers using C-style comments manually.

distro: Add Libusb.

* distro/packages/libusb.scm: New file.
* Makefile.am (MODULES): Add it.