Pullup changes since RC2. Fixes:

* WorldWind layer working again
 * Popup.destroy() complaints
 * Decompose marker destruction code for easier subclassing.
 * Error catching for better layerPx error in Map.js
 * Several eamples, including getFeatureInfo, fullScreen, worldwind,
   layer-opacity


git-svn-id: http://svn.openlayers.org/branches/openlayers/2.1@1501 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Util.js

@@ -148,6 +148,7 @@ OpenLayers.Util.onImageLoadErrorColor = "pink";
 
 OpenLayers.Util.onImageLoadError = function() {
     this.style.backgroundColor = OpenLayers.Util.onImageLoadErrorColor;
+    this.style.display = "";
 };