nsf.c

- Replaced hash-table for GetAllInstances() with a linear list. As a result, mass-destroy on exit is now much faster. Valgrind reports that the full cicrcle of creating 100.000 objects and destroying it on exit became about 15% faster. - added additional argument adEnd to CmdListAdd() - renamed CmdListRemoveList() to CmdListFree() - improved code documentation - removed unneeded AddInstance() and RemoveInstance() - deactivated uncalled ReverseLookupCmdFromCmdTable() and GetHiddenObjectFromCmd() since apparently not needed any more