Ported changes to CCopasiDataModel.cpp from Build-19 to HEAD.
Ported changes to CCopasiDataModel.cpp from Build-19 to HEAD.

jonasfoe/COPASI,jonasfoe/COPASI,copasi/COPASI,copasi/COPASI,copasi/COPASI,jonasfoe/COPASI,jonasfoe/COPASI,jonasfoe/COPASI,copasi/COPASI,copasi/COPASI,jonasfoe/COPASI,copasi/COPASI,jonasfoe/COPASI,jonasfoe/COPASI,copasi/COPASI,copasi/COPASI,jonasfoe/COPASI,copasi/COPASI