+ * @param exception_on_error whether we throw an exception or not
+ * @param enable_sequences = true to allow the header
+ * to be parsed *inside* the SeQuences,
+ * when they have an actual length
+ * \warning enable_sequences *has to be* true for reading PAPYRUS 3.0 files
+ * @param ignore_shadow to allow skipping the shadow elements,
+ * to save memory space.
+ * \warning The TRUE value for this param has to be used
+ * with a FALSE value for the 'enable_sequence' param.
+ * ('public elements' may be embedded in 'shadow Sequences')