* added a subclasses for line, spline and freehandcurve (parent is simple curve)
* started to implement transfer function for simplecurves, it will transfer a qpainterpath into values. the qpainterpath will come from the simple curves.
* kissplinecurvewidget is the first of the new widgets, that uses a kiscurve. currently only in the paint method, but the calculation is already in kissplinecurve
* other smaller refactorings..