Possibilty to add simple disc or cylinder layers to a tracking volume
Created GenericLayerBuilder which can create simple disc or cylinder layers. Added LayerProvider and LayerArrayCreator to TrackingVolumeBuilder to create layers within tracking volumes. Changed creation of EndCapVolumes. In LayerArrayCreator changed estimation of the position of arbitrary navigation layers and added possibility that no navigation layers needs to be created, when layers are attached to each other.