Implementation of a new method: the reference point method

[gialmisi]

The reference point method described in this article needs to be implemented. The scalarization functions needed have already been implemented. A function that computes k+1 solution candidates based on a given reference point needs to be implemented after which the method can be considered to be available in DESDEO. This function should be in a file found in the desdeo-mcdm package. A good example can be found in the current NIMBUS implementation on how the file with the reference point method could be structured. The implementation should be documented and tested.

This issue is related to the re-structuring of DESDEO, see the branch desdeo2.