Remove trailing whitespace.

Signed-off-by: Edward Z. Yang <edwardzyang@thewritingpot.com>

library/HTMLPurifier/Strategy/Composite.php

@@ -5,20 +5,20 @@
  */
 abstract class HTMLPurifier_Strategy_Composite extends HTMLPurifier_Strategy
 {
-    
+
     /**
      * List of strategies to run tokens through.
      */
     protected $strategies = array();
-    
+
     abstract public function __construct();
-    
+
     public function execute($tokens, $config, $context) {
         foreach ($this->strategies as $strategy) {
             $tokens = $strategy->execute($tokens, $config, $context);
         }
         return $tokens;
     }
-    
+
 }