circleci: Install packages ourselves

Start installing Python dependencies and Sphinx itself as part of the
CircleCI job rather than expecting it to be done in the Docker
container. This ensures we will use the version of the packages for a
given commit.

This is the other half of sphinx-doc/docker-ci#1.

Signed-off-by: Stephen Finucane <stephen@that.guru>

.circleci/config.yml

@@ -6,4 +6,6 @@ jobs:
     working_directory: /sphinx
     steps:
       - checkout
+      - run: /python3.4/bin/pip install -U pip setuptools
+      - run: /python3.4/bin/pip install -U .[test,websupport]
       - run: make test PYTHON=/python3.4/bin/python