Added form factor for prism3 (of IsGISAXS) and adapted DWBASimulation to deal with multiple particles

Conflicts:
	Core/Samples/inc/ISample.h
	Core/Samples/inc/Layer.h

Rewritten IsGISAXS Example 3 code using the new Experiment class (2): added MultiLayerDWBASimulation class.

Conflicts:
	Core/Samples/inc/ISample.h
	Core/Samples/inc/Layer.h

Refactored decorator classes, added Experiment, Beam and Detector classes and added prototype pattern to many classes (clone() function)

Adapted to directory structure

Conflicts:
	Core/Core.pro

Conflicts:
	App/App.pro
	App/src/TestDiffuseReflection.cpp
	App/src/TestFactory.cpp
	Core/Core.pro

All composite objects are now derived from ICompositeSample, which in turn is a tree of ISample objects.