URLs of the running examples also fixed

Github aggresively redirects path-URLs from https to http breaking
the nice relative URLs for the iframe and leading to mixed content
... again.
Fixed the library URLs in the examples themselves
Fixed the URLs of the flag images

This isn't really necessary yet, because browsers currently don't block
mixed-content images, but it fixes the warnings on the JS console.
Merge pull request #2 from hho/patch-2

Make it work with https everywhere