Minor code improvements in Renderer

-Removed some console output
-Put initialization of SDL in a separate functionn
-Put loading of assets in a separate function
Minor code cleanup in GameManager

-Added InitMenu() function to handle menu setup.
-Removed reseting of local/remote player info since this is done in
Restart()
-Moved reseting of Ball and Tile count to ResetBoard, since this is
where all Balls and Tiles get delted
Split AddBall into several functions

Added functions
-bool CanPlayerFireBall( Player )
    Returns true if Player has enough lives ( > 0 )
-shared_ptr< Ball > LaunchBall( Player, uint32_t ballID )
    Creates a ball and set stats
-IncreasePlayeAcitveBalls( Player )
    Increases ActiveBalls and removes the caption if local player
-double GetBallSpeed( Player )
    Gets Ball speed for Player in argument
Split up RemoveBall()

Added function RediceActiveBalls()
    -Reduces activa balls for owner
    -Reduces lives for owner if lives is 0 after reduction
    -Sends BallKilleMessage if Owner is local
-Removed updating of Player lives in Renderer ( this is already handled )