Player_api: Integrate settable player collisionbox

game_api.txt

@@ -331,6 +331,7 @@ The player API can register player models and update the player's appearence
 			bar = {x = 20, y = 39},
 		-- ...
 		},
+		collisionbox = {-0.3, 0.0, -0.3, 0.3, 1.77, 0.3}, -- In nodes from centre of feet
 	}