FRVR chat based games support

A quick list on the items we talked in July 12 meeting:

• Allow Cross-origin requests from within the webview/iframe - XMLHttpRequests - Mandatory
• Ability to obtain context info about users, rooms - multiplayer context within the webview/iframe - Mandatory
• Webhooks: RC should alert the game when a session ends; specific SECURED/authenticated webhook endpoint that is callable externally to indicate end of game - highest priority AFTER mandatory
• Storage for the games, scoped by user; this is NOT localstorage but a server-side storage mechanism accessible from within the webview/iframe
• Enable “game user” to communicate with users; this can be and should be integrated with our core-competence - CHAT flow
• Cross promoting games mechanism - enable games to switch between themselves (FBInstant.swtichGameAsync); this means one UI app must be able to invoke another UI app with state transfer; furthermore, it means that from a user-experience perspective the app changes within the iFrame/webview WITHOUT opening and closing or other distractive effects
• Optimize strategy in CDN caching of static and semi-static assets; to be worked out with FRVR.