This reverts commit e202d1ef.

Status: FitTest02 fails.

- 3rd person form: "Does" this or that.
- For all const methods that return something: "Returns" ...
- For boolean return value: "Returns true if " ...

manual editing of @brief ("defines ...", "implements ..."), removed multiple white lines

Moved to usage of IChiSquaredModule interface (instead of concrete class pointers) + moved getChi2DifferenceMap from FitSuiteObserverDraw to IChiSquaredModule

TestFittingModule switched to new FitSuite, Observer pattern and new FittingHelper to follow fit iterations