BUG: refs #0361. Fix downloading of zips

We had newlines prepended and a warning added at the end of our zip file,
which was breaking the windows opener (and probably others too...)

Author: zachmullen

core/controllers/DownloadController.php

@@ -134,6 +134,11 @@ public function indexAction()
         }
       else
         {
+        while(ob_get_level() > 0)
+          {
+          ob_end_clean();
+          }
+        ob_start();
         Zend_Loader::loadClass('ZipStream', BASE_PATH.'/library/ZipStream/');
         $this->_helper->viewRenderer->setNoRender();
         $name = $revision->getItem()->getName();
@@ -144,6 +149,7 @@ public function indexAction()
           $zip->add_file_from_path($bitstream->getName(), $bitstream->getAssetstore()->getPath().'/'.$bitstream->getPath());
           }
         $zip->finish();
+        exit();
         }
       }
     else
@@ -175,9 +181,16 @@ public function indexAction()
         {
         $name = "Custom";
         }
+
+      while(ob_get_level() > 0)
+        {
+        ob_end_clean();
+        }
+      ob_start();
       $zip = new ZipStream($name.'.zip');
       $zip = $this->_createZipRecursive($zip, '', $folders, $revisions);
       $zip->finish();
+      exit();
       }
     }//end index