Fix Maxit game demo

In the Maxit Single Player problem there is a demo, which seems to have cross-browser compatibility flaw as kindly reported by colleague spudowiar - see details.

I moved the script out of the problem page to github, so here is the project and demo at github pages.

The problem page loads script from github also - so all we need - some volunteer to fork it, fix it and create pull request :)

Thank you in advance!