Namespace everything into FrenzyGames.Fruitgame.

This will allow us to use third-party scripts that use the default namespace with conflicting script names. And really, it's just good style
Import PPrefsSocialPlatform: local achievements/leaderboards

https://www.assetstore.unity3d.com/#/content/3760
GameOverEvent is broadcasted as an event.

This only happens with ForceGameOver, not quit-to-title.
Configure local achievements/high score lists.
Scores are recorded. #64

No UI to display them yet, but they're Debug.Log()'ed when the game starts up.
Prettier highscore list logging. #64
Show high score list from main menu. #56, fixes #64

GUIMainMenu should eventually replace MainMenu when #56 is done.

Configurable maximum of 50 scores shown.