- Add behavioural setting to loop from last slide to first slide
  and vice versa
- Add behavioural setting to progress to next slide automatically
- Add behavioural setting to set time period after which to
  autoprogress
- Add behavioural setting to hide navigation elements; will hide
  progress bar and button symbols, but keep dark background on
  mouse hover over navigation area at left/right border. Navigation
  with mouse and keys is still possible
- Move aspect settings into behavioural settings group