* 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

Refactor model: distribution items

See merge request !219

rm IComponent

See merge request !218

Some minor renaming of functions of the distribution items to be consistent with other function names

Refactor SimulationOptionsItem for strong typed methods

See merge request !217

Correct intensities for source or detector below the horizon

Closes #100

See merge request !216

Prepare for generalization of kz and TR computation

See merge request !215

Core: get rid of ISpecularStrategy hierarchy

See merge request !214