Update demos that do not include API keys

[rmglennon]

It looks like a few of these demos are missing API keys -- mostly, the simpler ones without configuration files.

Let's fix up any of these that rely on keyless access that need to continue to function. For example, the isochrone demo is linked to from a blog post.

PS - while you're in there, please fix the typo in a href="http://openstreetmap.org">OpenStreetMap contributers ---> contributors. :)