FF: image-based classes should use BaseVisual for contains() and overlaps()
DOC: fix comment in RatingScale
Merge branch 'master' of github.com:psychopy/psychopy
Merge branch 'master' of git://github.com/psychopy/psychopy

* 'master' of git://github.com/psychopy/psychopy:
  FF: image-based classes should use BaseVisual for contains() and overlaps()
ENH: RatingScale marker='hover'

- nice and minimal: effectively just a clickable set of text choices