Changed default constructor from privat to protected so that we can create default constructors for derived classes.
Changed default constructor from privat to protected so that we can create default constructors for derived classes.

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