Start with no alpha so getting a paint before we're ticked doesn't blow up

git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@495 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/media/animation/GleamAnimation.java

@@ -203,7 +203,7 @@ public class GleamAnimation extends Animation
     protected int _downmillis;
     protected int _maxAlpha = 750;
     protected int _minAlpha;
-    protected int _alpha = -1;
+    protected int _alpha;
     protected long _lastUpdate;
     protected int _millisBetweenUpdates;
 }