Vocab widget: updated demonstrator to include new advanced mode
Vocab widget: updated narrow, broad SISSVOC urls to get just children/parent, not descendants/ancestors
minor changes to the Vocab widget:
  - better 'mode' handling
  - removed defaults for mode, repository
  - renamed widget from ands_vocab_widget to vocab_widget
Vocab widget: updated demonstrator, documentation, css to reflect widget changes (advanced mode, events, configuration defaults, widget name, style names)