Fix #42: sampling bug in egs_shape_collection

The shape getPoint() method returns a point in the shape WITHOUT
applying its affine transformation. The shape collection must instead
call the getRandomPoint() method which applies the transformations
defined for each shape.

HEN_HOUSE/egs++/shapes/egs_shape_collection/egs_shape_collection.h

@@ -110,7 +110,7 @@ class EGS_SHAPE_COLLECTION_EXPORT EGS_ShapeCollection : public EGS_BaseShape {
  };
  EGS_Vector getPoint(EGS_RandomGenerator *rndm) {
  int j = table->sampleBin(rndm);
- return shapes[j]->getPoint(rndm);
+ return shapes[j]->getRandomPoint(rndm);
  };
 
  bool supportsDirectionMethod() const {