BF: Replaced iohub eye_tracker demo update

- images are all now ones taken by Sol Simpson; free to use in any way
by anyone, license.
- all images are now jpg, none larger than 460 K.
Merge branch 'master' of git://github.com/psychopy/psychopy
updated .gitignore to skip .bak files
Merge pull request #327 from isolver/master

BF: Replaced iohub eye_tracker demo update