Removes remnant of escaped special characters.

Before `urlFor` would return '/path/Hello\.Josh' for a pattern
'/path/(:foo\.:bar)' with parameters
`('foo' => 'Hello', 'bar' => 'Josh')`, when the expected return value
is '/path/Hello.Josh' (this test was introduced in commit cc722cc).

Slim/Router.php

@@ -192,8 +192,8 @@ public function urlFor($name, $params = array())
         }
         $pattern = preg_replace($search, $params, $this->getNamedRoute($name)->getPattern());
 
-        //Remove remnants of unpopulated, trailing optional pattern segments
-        return preg_replace('#\(/?:.+\)|\(|\)#', '', $pattern);
+        //Remove remnants of unpopulated, trailing optional pattern segments, escaped special characters
+        return preg_replace('#\(/?:.+\)|\(|\)|\\\\#', '', $pattern);
     }
 
     /**