v2.2.0: substantially improved crystal wisp visuals

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

@@ -67,8 +67,14 @@ public class Halo extends Image {
 		this.y = y - (height()/2f);
 		return this;
 	}
-	
-	public void radius( float value ) {
+
+	@Override
+	public void alpha( float value) {
+		brightness = value;
+		super.alpha(value);
+	}
+
+	public void radius(float value ) {
 		scale.set(  (this.radius = value) / RADIUS );
 	}
 }