add captcha points cache

+diff --git a/captcha.inc b/captcha.inc
+index 4dc6f82..eb8b584 100644
+--- a/captcha.inc
++++ b/captcha.inc
+@@ -64,6 +64,7 @@ function captcha_set_form_id_setting($form_id, $captcha_type) {
+       'warning'
+     );
+   }
++  cache_clear_all('captcha_points:' . $form_id,'cache_captcha');
+ }
+ 
+ /**
+@@ -82,18 +83,21 @@ function captcha_set_form_id_setting($form_id, $captcha_type) {
+  *   or in the form 'captcha/Math'.
+  */
+ function captcha_get_form_id_setting($form_id, $symbolic = FALSE) {
+-  // Fetch setting from database.
+-  if (module_exists('ctools')) {
+-    ctools_include('export');
+-    $object = ctools_export_load_object('captcha_points', 'names', array($form_id));
+-    $captcha_point = array_pop($object);
+-  }
+-  else {
+-    $result = db_query("SELECT module, captcha_type FROM {captcha_points} WHERE form_id = :form_id",
+-      array(':form_id' =>  $form_id));
+-    $captcha_point = $result->fetchObject();
+-  }
++  
++  $cache_key = 'captcha_points:' . $form_id;
+ 
++  $cache = cache_get($cache_key,'cache_captcha');
++  $captcha_point = false;
++  if($cache && !empty($cache->data)){
++    $captcha_point = $cache->data;
++  }else{
++    $captcha_points = captcha_get_captcha_points();
++    if(isset($captcha_points[$form_id])){
++      $captcha_point = $captcha_points[$form_id];
++      cache_set($cache_key,$captcha_point,'cache_captcha',CACHE_PERMANENT);
++    }
++  }
++  
+   // If no setting is available in database for the given form,
+   // but 'captcha_default_challenge_on_nonlisted_forms' is enabled, pick the default type anyway.
+   if (!$captcha_point && variable_get('captcha_default_challenge_on_nonlisted_forms', FALSE)) {