Fixes #600. Provides a fix for crashing home page.

The index controller does not properly handle errors and does not properly check for null or undefined indices in the list of articles it is provided.  When it passes a null or undefined value the meta info is gathering is skipped causing a failure when the callback is returned and the error is not handled.

include/service/entities/article_service.js

@@ -476,7 +476,17 @@ module.exports = function ArticleServiceModule(pb) {
      */
     ArticleService.prototype.getMetaInfo = function(article, cb) {
         if (util.isNullOrUndefined(article)) {
-            return cb(new Error('The article parameter cannot be null'));
+            return cb(
+                new Error('The article parameter cannot be null'),
+
+                //provided for backward compatibility
+                {
+                    title: '',
+                    description: '',
+                    thumbnail: '',
+                    keywords: []
+                }
+            );
         }
 
         //compile the tasks necessary to gather the meta info