Enable support for Google Cloud Endpoints

[Scarygami]

Reference: https://developers.google.com/appengine/docs/python/endpoints/consume_js

[ebidel]

Why not make this just param something like appId instead,...and not require the user to set a full URL?

[Scarygami]

Good point, this will work since cloud endpoints don't support custom domains, so the URL format is fixed anyway.

[Scarygami]

Hmmm, thinking about it there's one scenario when you would need a different root URL:
When testing in local dev-environment you would use http://localhost:port/_ah/api

Should I add both root and appId attributes?

And which one would be better to have higher priority?

1. Overwrite root when an appId is present, or
2. ignore appId when root is present (I think this option would be better)

[ebidel]

appId = localhost:port would still work. We can probably just document that case for local dev. WDYT?

[Scarygami]

With the current implementation this would result in https://localhost:port.appspot.com/_ah/api which would fail.

[ebidel]

Right sorry. Maybe this should be a cloudEndpointHost param?

[Scarygami]

Hmmm, the simplicity of just having the appId is nice though.
Maybe leave it like this for now, since it covers most use-cases, and keep it in mind as further enhancement?

From my experience testing cloud endpoints on the local dev-server is a little bit wonky anyway, and not quite the same like running it directly on App Engine.

[ebidel]

Future improvement :) Mind logging a bug so we can keep track of it?