DOC: rst for demo style guide
BF: better shebang (python2); ref issue #486

- disambiguates python2 from python3 for people with both, eg, ArchLinux
- all tests passing
- visual.Window had improper ##/usr/bin/env (two #); now cleaned-up
BF: fix python22 (revert)
Merge pull request #489 from jeremygray/master

shebang -> python2