Save and load the game state

[otternq]

Allow the user to save the game state. We are considering two options:

• Google Play Game Services
• Google App Engine (through Google App Engine Endpoints)

[otternq]

My preference is Game Services simply because that allows us to interact with one web service for our storage / sharing needs.

[jleithart]

I'll take a look at Google Play Game services this weekend after I get my layout fixed.