Merge pull request #252 from jeremygray/master

BF RatingScale wrapWidth in scale description
ENH: better control of mirroring in Text components; + changelogs

- can now do dynamically using $var_name, e.g., from a conditions file
- simpler dialog box (enter 'horiz', 'vert', or '$var_name')

(I'll use this feature soon for a mental rotation task.)