1.0.0
        - Initial version

2.0.0
        - The method initialise() need not be implemented
          anymore in sub classes of the class template Problem.
        - Further methods related to the initialisation of the data fields
          like init() were deleted.
	- Memory management was reorganized: Memory will be not allocated
	  anymore separately in each DataField, but in the class Problem.
	  resulting in one single memory lump of the new resp. the
	  old iterate.

