fixed bug

fixed bug:

functions:

    newt_checkbox_tree_get_selection

    newt_checkbox_tree_get_multi_selection

    newt_listbox_get_selection

    newt_checkbox_tree_set_entry_value

    newt_checkbox_tree_get_entry_value

    newt_checkbox_tree_find_item

    newt_checkbox_tree_set_entry

   newt_checkbox_tree_add_item