Merge pull request #729 from isolver/master

BF: iohub eye tracker calibration (for tobii and eyelink) keyboard event fix
ENH: enable RatingScale scale='xyz' when using choices
Merge pull request #731 from jeremygray/master

ENH: enable RatingScale scale='xyz' when using choices
DOC: changelog update
Merge pull request #732 from jeremygray/master

DOC: changelog update
Changed eyelink config default setting
Merge branch 'master' of git://github.com/psychopy/psychopy
BF: FutureWarning fixed

When running python 2.7.7 I was getting the following warning from
shape.py:

> FutureWarning: comparison to `None` will result in an
> elementwise object comparison in the future.

Fixed by changing "!=None to "is not None".
ENH: gcCursor eye tracker demo

Now by default no eye tracker config is enabled in iohub_config for
experiment. If demo is run, error dialog is displayed. User must
explicitly uncomment the eye tracker config for the ET hardware being
used to run the demo.