Fix OpenGl rendering by installing missing SW rendering library

Author: mobernabeu

Dockerfile

@@ -15,6 +15,7 @@ RUN apt-get update \
  language-pack-zh-hant language-pack-gnome-zh-hant firefox-locale-zh-hant libreoffice-l10n-zh-tw \
  nginx \
  python-pip python-dev build-essential \
+ mesa-utils libgl1-mesa-dri \
  && apt-get autoclean \
  && apt-get autoremove \
  && rm -rf /var/lib/apt/lists/*