Add 'loadstart' and 'loadend' events to some of our exciting layers like WFS, GML, GeoRSS, and Text. tests to back it up. (Closes #808)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@4252 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Tile/WFS.js

@@ -75,6 +75,13 @@ OpenLayers.Tile.WFS = OpenLayers.Class(OpenLayers.Tile, {
      */
     draw:function() {
         if (OpenLayers.Tile.prototype.draw.apply(this, arguments)) {
+            if (this.isLoading) {
+                //if already loading, send 'reload' instead of 'loadstart'.
+                this.events.triggerEvent("reload"); 
+            } else {
+                this.isLoading = true;
+                this.events.triggerEvent("loadstart");
+            }
             this.loadFeaturesForRegion(this.requestSuccess);
         }
     },
@@ -121,6 +128,9 @@ OpenLayers.Tile.WFS = OpenLayers.Class(OpenLayers.Tile, {
                 this.addResults(resultFeatures);
             }
         }
+        if (this.events) {
+            this.events.triggerEvent("loadend"); 
+        }
     },
 
     /**