add a bunch of system packages

.gitlab-ci.yml

@@ -14,12 +14,13 @@ westpy_build:
    - apt-get install -qq build-essential > /dev/null
    - apt-get install -qq apt-utils > /dev/null
    - apt-get install -qq pkg-config > /dev/null
+   - apt-get -qq install libpng12-dev > /dev/null
+   - apt-get install -qq pandoc > /dev/null
    - apt-get install -qq libfreetype6-dev > /dev/null
    - apt-get install -qq git >/dev/null
    - apt-get install -qq wget git > /dev/null
    - apt-get -qq install zlib1g-dev > /dev/null
    - apt-get -qq install libssl-dev > /dev/null
-   - apt-get -qq install libpng12-dev > /dev/null
    - cd /opt
    - export PY_VERSION="3.5.6"
    - wget https://www.python.org/ftp/python/$PY_VERSION/Python-$PY_VERSION.tgz