fixes for using the new module system

doc.zih.tu-dresden.de/docs/quickstart/getting_started.md

...tu-dresden.de/docs/software/data_analytics_with_python.md

doc.zih.tu-dresden.de/docs/software/data_analytics_with_r.md

doc.zih.tu-dresden.de/docs/software/machine_learning.md

...esden.de/docs/software/misc/tensorflow_jupyter_module.png

doc.zih.tu-dresden.de/docs/software/nanoscale_simulations.md

...u-dresden.de/docs/software/python_virtual_environments.md

doc.zih.tu-dresden.de/docs/software/tensorflow.md