The `init` method now accepts an optional Facebook `accessToken`.

Breaking change: `init` takes an optional `options` arguments, which replaces the optional `redirectURL` & `store` arguments. See `init` method for details.

There are several scenarios in which your app might already have a valid `accessToken`. One example: if you use the [Cordova Facebook Plugin](https://github.com/phonegap/phonegap-facebook-plugin) for SSO (single sign-on).