changed forward movement to be physics based

Previously the movement was translation based which caused problems with the powerup raycast collisions at higher speeds.  It didn't take too long to change things to physics based and pass control of player movement to the player object rather than the game overlord object.  Also messed with the wall particles and a small change made the flames look so much better.  I still need to change the collisions with the obstacles to be physics based but I don't think players will mind occasionally being missed at higher speeds.