gnu: Add python-waitress.

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

gnu: Add python-beautifulsoup4.

* gnu/packages/python.scm (python-beautifulsoup4, python2-beautifulsoup4):
  New variables.

gnu: Add python-pytest-xdist.

* gnu/packages/python.scm (python-pytest-xdist, python2-pytest-xdist):
  New variables.

gnu: Add python2-execnet.

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

gnu: Add python2-apipkg.

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

gnu: Add python-alembic.

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

download: Add 'url-fetch/tarbomb'.

Suggested by Federico Beffa.
Fixes <http://bugs.gnu.org/22676>.
Reported by Danny Milosavljevic <dannym@scratchpost.org>.

* gnu/packages/engineering.scm (broken-tarball-fetch): Remove.
(fastcap)[source](method): Use URL-FETCH/TARBOMB instead.
* gnu/packages/scheme.scm (broken-tarball-fetch): Remove.
(scmutils)[source](method): Use URL-FETCH/TARBOMB instead.
* guix/download.scm (url-fetch/tarbomb): New procedure, renamed from
'broken-tarball-fetch'.

gnu: icu4c: Fetch from sourceforge.

* gnu/packages/icu4c.scm (icu4c): Download via sourceforge mirrors.  The
  previous URL,
  http://download.icu-project.org/files/icu4c/55.1/icu4c-55_1-src.tgz,
  redirects to sourceforge, which then fails because that redirects to
  https and as the original URL didn't start with HTTPS, gnutls wasn't
  included in the downloader.

Update all sources from freedesktop.org to use https

* gnu/packages/xorg.scm:
* gnu/packages/xdisorg.scm:
* gnu/packages/video.scm:
* gnu/packages/tls.scm:
* gnu/packages/python.scm:
* gnu/packages/pulseaudio.scm:
* gnu/packages/polkit.scm:
* gnu/packages/pdf.scm:
* gnu/packages/libcanberra.scm:
* gnu/packages/gtk.scm:
* gnu/packages/gstreamer.scm:
* gnu/packages/gnome.scm:
* gnu/packages/glib.scm:
* gnu/packages/ghostscript.scm:
* gnu/packages/freedesktop.scm:
* gnu/packages/fontutils.scm: Update all sources hosted on freedesktop
  to fetch tarballs via https.  freedesktop.org appears to have updated
  recently to redirect all http to https.  As an exception, we leave
  pkg-config like it is, because pkg-config is needed to build gnutls,
  and without gnutls we can't download https URLs.

gnu: libx264: Update to 20160220-2245.

* gnu/packages/video.scm (libx264): Update to 20160220-2245.

gnu: xvid: Use 'modify-phases'.

* gnu/packages/video.scm (xvid)[arguments]: Use 'modify-phases'.

gnu: xvid: Update to 1.3.4.

* gnu/packages/video.scm (xvid): Update to 1.3.4.

linux-modules: Use normalized module names for 'modprobe.blacklist'.

* gnu/build/linux-modules.scm (normalize-module-name): New procedure.
(file-name->module-name): Use it.
(module-black-list): Expound docstring.

gnu: linux-libre: Update to 4.4.2.

* gnu/packages/linux.scm (linux-libre): Update to 4.4.2.

gnu: python-enum34: Remove python-setuptools from inputs.

* gnu/packages/python.scm (python-enum34)[inputs]: Remove
python-setuptools.

gnu: Don't use python-enum34 when building with python-3.4.

* gnu/packages/docker.scm (docker-compose)[inputs]: Remove python-enum34.
* gnu/packages/python.scm (python-parse-type)[inputs]: Likewise.
(behave)[inputs]: Likewise.
(python-cryptography)[propagated-inputs]: Likewise.
(python2-cryptography)[propagated-inputs]: Add python2-enum34.

gnu: Add python2-enum34.

* gnu/packages/python.scm (python2-enum34): New variable.

gnu: python-enum34: Update to 1.1.0.

* gnu/packages/python.scm (python-enum34): Update to 1.1.0.
[source]: Use pypi-uri.

gnu: dvtm: Update to 0.15.

* gnu/packages/dvtm.scm (dvtm): Update to 0.15.

gnu: abduco: Update to 0.5.

* gnu/packages/abduco.scm (abduco): Update to 0.5.