Add support for sending messages marked as transient
Added new API that overloads the existing sendMessage() API with an additional parameter 'isTransient'. The new flag allows the device to skip processing of the sent message if the volume of the messages from the companion app is too high.
Add support for UniversalLinks to open the example app
Instead of using URLScheme to let the GCM open the example app attempt to use the universal links to open it.