…ster

- The dockerfiles build successfully.
- Compared to current master, there's a new intermediate image for
  glibc.  As the x86_64 build depends on it, this must have a predefined
  name.  In the PR the "naming prefix" is 'markrwilliams/manylinux2',
  therefore it's assumed for all images.
- There's a problem with libcurl which has been (temporarily) resolved
  with script which redirects yum.  See docker/build_scripts/build.sh for
  details.

The following script is proven to work:

  pushd docker/glibc/
  docker build -t markrwilliams/manylinux2:centos-6.9-no-vsyscall
  popd
  docker/build_scripts/prefetch.sh curl openssl
  docker build -t markrwilliams/manylinux2:x86_64 \
    -f docker/Dockerfile-x86_64 docker/
  docker build -t markrwilliams/manylinux2:i686 \
    -f docker/Dockerfile-i686 docker/

- docker/build_scripts/build.sh:
  - removed libncurses.devel; not part of PEP 571
  - removed gpg as dependency, because yum already requires it
  - removed some /dev/null redirections, because they hinder debugging

- docker/build_scripts/manylinux1-check.py
  - renamed to manylinux-check.py
  - changed names/comments to new version
  - the check now targets glibc 2.12 instead of 2.5

- .travis.yml
  - only changed the image name
  - TODO: x86_64 still needs a script for the no-vsyscall image dependency

- docker/deploy.sh
  - changed image name

- note: .rst files have not been touched

- The freshly released version of pip breaks build_utils.sh which tries
  to get the latest and greatest.  Added a condition to instead use the
  latest version below v10.

- Incorporated the lastest changes from the official repository.
  - That cleanup removed two packages from 'yum erase ...' which looks
    like an oversight. Readded.
- Removed the hack which fixed the broken build when the new pip was
  released.  This has been fixed upstream, see here:
  pypa/get-pip#19

- Add platform-dependent clause
- Assign the same prefix to the the no-vsyscall image (quay.io/pypa/...)
- The dependent docker/Dockerfile-x86_64 needs this prefix in FROM ...

- Increase in `travis_wait` time
- Shunting build output off into a log file which can be inspected
  on failure.

is merge is necessary,

- Similar to gpg the libffi-devel package can't be removed after the
  build, but it looks like this is because it was improperly packaged.
- Moved libffi to the "Development tools and libraries" section.

Like with CentOS 5 there's a CentOS 6 Docker image which is more up to
date (tag :6) than the latest release (tag :6.9).
See: pypa#206

Previously, vault.centos.org was missing some repository information,
which prevented moving to 6.10.  This is now available on CentOS 6.10
and it includes a glibc v1.212 (up from 1.209).  All changes made are
only to bump this version number.