- Remove communication via DBus, replaced by KProcess
  - Supports text result for a python expression with plot image result
  - Show numpy arrays in full form (because we had solved problem with showing big strings in the variable model)
  - Use Session::setVariableModel instead of handling variable model by self
  - Better interrupt
  - Use expression queue, model updating and expression finishing from Session
  - Remove unused PythonSession members
  - Some tests improvments

Closes T6113, T6114
Differential Revision: https://phabricator.kde.org/D21212