Cordova 3.1.0 support added for the new amazon-fireos platform. Broadcast receiver added.

There is new platform type `amazon-fireos` since Cordova 3.1.0. I changed the `plugin.xml` to support the new platform instead of the android platform.

I fixed also the bug where the broadcast receiver is not added to the `AndroidManifest.xml`.

Thanks for this great plugin :)