pass current document to views, so they work on this document, not with global pointers and MainWindow

use radio buttons instead of comboboxes for 2-choice-options; fix missing update on project load; add missing "document modified" after editing; refine UI

* introduce QtDesigner ui file for SimulationView
* move code spreaded over related UI classes to SimulationView
* remove these obsolete UI classes
* remove generic UI creation (SessionItem/-Model)

All of the above increases maintainability and eases understanding of the code base