ENH: _baseVisualStim polygon centroid()

- add _baseVisualStim.centroid()
- calls visual.polygonCentroid() == vectorized centroid calc
- add to demo
- refactor .overlaps() to pull out common code (tests pass)
BF: wrong argument name in psychopy.visual.CustomMouse
revert centroid()

- down-voted by JWP as not widely useful
- keep refactoring of _getPolyAsRendered()
ENH: print a file from Coder; closes #224

ultra-basic printing, no control over anything
Merge pull request #228 from jeremygray/master

print a file from Coder
Merge pull request #229 from hsogo/master

BF: wrong argument name in psychopy.visual.CustomMouse 
RatingStim: Added tickMarks and labels argument, changed behavior of choices
RatingStim: restored default choices behavior, added ticksAboveLine argument
RatingScale: Updated doc for tickMarks argument
RatingScale: Update doc for tickMarks argument
RatingScale: labels=False default, added oldChoiceBehavior to builder component

Furthermore, updated docs for RatingScale class.
ENH Builder namespace: update list of names to check

(and adjust lots of indentation & long lines)
DOC: typo in comment about experiment code generation
check box renamed to "choiceLabelsAboveLine", removed __author__
ENH: Added setOri to visual.Aperture
RatingScale choices (builder) keep old behavior
small clarification in code comment
Merge pull request #230 from singmann/master

RatingScale: New arguments tickMarks and labels, new behavior for choices
Merge pull request #232 from thomastweets/master

ENH: Added setOri to visual.Aperture
RF: launch firstrun and benchmark wizards as separate python processes

- refactored to avoid needing app; will change file name & path to reflect this
- save firstrun.html file separately from benchmark.html
- reports saved in userPrefsDir (overwritten if you run the wizard again)
- can now run benchmark from Coder menu too