Demo still broken by strict mime-type checking

[wizzard0]

Same as #6

2017-05-21 14:08:42.263 satyr.github.io/:1 Refused to execute script from 'https://github.com/satyr/coco/raw/master/extras/coco.js' because its MIME type ('text/plain') is not executable, and strict MIME type checking is enabled.