Future Android tutorial topics

[ajhager]

• Cross platform web requests, github.com/square/retrofit
• Using interfaces to inject per platform functionality to core module (saving and loading fortune file)
• Cross platform Data table UI (showing / editing saved fortunes)
• Event Bus, gitthub.com/square/otto, to decouple events from UI updates
• Lifecycle considerations, especially with async tasks
• Switch to using lambdas, show how to use retrolambda on Android.