v0.4.3: implement seeds into levelgen (not currently user enterable)

SPD-classes/src/main/java/com/watabou/noosa/Group.java

@@ -22,6 +22,7 @@
 package com.watabou.noosa;
 
 import com.watabou.noosa.particles.Emitter;
+import com.watabou.utils.Random;
 
 import java.util.ArrayList;
 
@@ -275,7 +276,7 @@ public class Group extends Gizmo {
 	
 	public synchronized Gizmo random() {
 		if (length > 0) {
-			return members.get( (int)(Math.random() * length) );
+			return members.get( Random.Int(length) );
 		} else {
 			return null;
 		}