Push notification support

Here we are adding a few things to the App Services portion of the SDK to support push. 

1. Adding device registration and update capabilities
  1. Now devices can be registered with the app services API via javascript
  2. UUID persistence support is added as well to track Apigee device ID we assign
2. Sending notifications to a specific path is supported as well
  1. We can send pushes to all the different paths supported by app services
  2. It performs a dynamic lookup of the notifier to figure out how to format the push envelop