added gitlab-ci YAML file

stages:

    - test

    - build

cache:

    paths:

        - runner-ve/

        - setuptools*

test-27:

    stage: test

    tags:

        - python27

    script:

        - virtualenv --python=python2.7 runner-ve

        - . runner-ve/bin/activate

        - pip install --upgrade pip setuptools

        - pip2 install -r requirements-27.txt

        - python2.7 setup.py test

test-3x:

    stage: test

    tags:

        - python3x

    script:

        - virtualenv --python=python3 runner-ve

        - . runner-ve/bin/activate

        - pip3 install --upgrade pip setuptools

        - pip3 install -r requirements-3x.txt

        - python3 setup.py test