Added LevelAPI

[Flowaria]

Open up often used LevelEvents

        /// Invoked when Level Data has Updated (This includes level change / seed change)
        public static event Action<ActiveExpedition, ExpeditionInTierData> OnLevelDataUpdated;

        /// Invoked when Level has Selected
        public static event Action<eRundownTier, int, ExpeditionInTierData> OnLevelSelected;

        /// Invoked when LevelBuild has started
        public static event Action OnBuildStart;

        /// Invoked when LevelBuild has finished
        public static event Action OnBuildDone;

        /// Invoked when Enter the level (Player is able to move)
        public static event Action OnEnterLevel;

        /// Invoked when Level has Cleaned up
        public static event Action OnLevelCleanup;