Reworking the documentation

The doxygen documentation has been written by the ones who initially developed the OSI 2.0.0. Therefore it is crucial that an outside person reads through the definitions carefully and extends the explanaitions accordingly. I would ask @carsten-kuebler to do this in the beginning of January after the updates end of December. The version 2.3.0 will be released with the updated documentation at the 26th of January.