Exoplayer activity for app - support remote control

[sentinelweb]

• make exoplayer activity with player controls
• setup remote launch
• volume controls
• play local file
• make a datasource for exoplayer that allows http
• transfer session to another screen
• try to launch app player on second screen
• setup cuercast controls in hub
• play controls for hub - bind to CastController
• animations to show/hide player controls
• save state (ordering at least) in filebrowser
• play movie on flip cover - make a cover activity to just have player (control remotely)
• make a fallback to just use standard android VideoPlayer - compare on different devices