Game: Add game state.

git-tfs-id: [https://tfs.codeplex.com:443/tfs/TFS15]$/Atomix;C39548
Logic: Remove LevelType from definition (as it is not needed for run).

git-tfs-id: [https://tfs.codeplex.com:443/tfs/TFS15]$/Atomix;C39549
Game: Move Input Manager to Screen Manager.

git-tfs-id: [https://tfs.codeplex.com:443/tfs/TFS15]$/Atomix;C39550