Added member variables to bobura::view::diagram::train_line_fragment.
Implemented bobura::view::diagram::train_line_fragment.
Changed the name; bobura::view::diagram::item::set_slected() to select().
Implemented bobura::diagram_view::unselect_all_items().
Implemented bobura::view::diagram::item::operator=().
Corrected a compilation error.
Implemented bobura::view::diagram::train_line_fragment.
Implemented bobura::view::diagram::selection.
Implemented bobura::view::diagram::item::select().
Implemented bobura::view::diagram::train_line_fragment::select_impl().
Implemented bobura::view::diagram::selection::selected().