Revert "Fix IPython shell colors on dark background"

This reverts commit 6623c20e10008562b2357dab0eed245ce77b779b.

Doesn't play nice with `py notebook`.
Revert "Use python-mode.el"

This reverts commit 4cd2ac0ec86b9681099efa3d24502173f5584cd8.

Sorry, don't really like it compared to standard Python mode. IPython
shell integration doesn't work for me like I hoped, and that was the
major reason for switching to python-mode.el.
Add new shark headnode to LUMC bashrc