general improvements for the course

[janverbesselt]

• investigate the potential for feedbackfruit within the geo-scripting class
• install virtualbox on the windows computers and test that? evaluate and compare with cloudbased solutions.
• include SQL session in the twittter lesson
• focus from the start on "modular programming"
• think about how to motivate students - to complete the self-study sessions
• improve structure of the python week, add a list of handy Python modules for spatial data handling and visualisation