RF: visual.RatingScale; many API changes

See changelogs
TEST: update test
RF: autoLog=False for text-element creation in RatingScale init
RF: RatingScale init: avoid creating unneeded TextStim
RF: revise Builder RatingScale demo

also autoLog=False for .line in ratingscale
DOC: tweaks to RatingScale API doc
DOC: tweaks to RatingScale API doc, use setAttrib

- use setattrib-style for pos, color, text, etc
Merge branch 'rf-ratingscale' of github.com:jeremygray/psychopy into rf-ratingscale

* 'rf-ratingscale' of github.com:jeremygray/psychopy:
  DOC: tweaks to RatingScale API doc

Conflicts in doc strings:
	psychopy/visual/ratingscale.py
RF: revert to setPos etc so can log=False

travis logs almost doubled using setAttrib-style assignments
Merge pull request #477 from jeremygray/rf-ratingscale

RF ratingscale