coding standards if statement should always be followed by braces. also, add comment

git-svn-id: http://svn.openlayers.org/trunk/openlayers@2987 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Events.js

@@ -146,8 +146,12 @@ OpenLayers.Event = {
      * 
      */
     _observeAndCache: function(element, name, observer, useCapture) {
-        if (!this.observers) this.observers = new Object();
 
+        //if observers cache has not yet been created, create it
+        if (!this.observers) {
+            this.observers = new Object();
+        }
+        
         //if there is not yet a hash entry for this element, add one
         if (!this.observers[element.id]) {
             this.observers[element.id] = new Array();