RF: RatingScale - refactoring

RF: extensive cosmetic refactoring for simpler code readability, minor efficiencies
ENH: new parameter 'acceptSize' (control width of acceptBox)
     good to allow user to set a size; looks bad if text spills over
BF: negative markerExpansion (for glow)
Merge pull request #290 from jeremygray/RF-ratingscale

RF: RatingScale - refactoring