Manually apply PR #1594 (fixing phpdoc page-level generation/warnings)

Also partially fixes issue #1295, fixes inconsistencies in some page-level docblocks and adds include checks in language files.
diff --git a/system/language/english/date_lang.php b/system/language/english/date_lang.php
index 6683e4c..db1e9e0 100644
--- a/system/language/english/date_lang.php
+++ b/system/language/english/date_lang.php
@@ -24,6 +24,7 @@
  * @since		Version 1.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 $lang['date_year'] = 'Year';
 $lang['date_years'] = 'Years';