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/migration_lang.php b/system/language/english/migration_lang.php
index 5753c00..714a1e3 100644
--- a/system/language/english/migration_lang.php
+++ b/system/language/english/migration_lang.php
@@ -24,6 +24,7 @@
  * @since		Version 3.0
  * @filesource
  */
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 $lang['migration_none_found']			= 'No migrations were found.';
 $lang['migration_not_found']			= 'No migration could be found with the version number: %d.';
@@ -33,6 +34,5 @@
 $lang['migration_missing_down_method']	= 'The migration class "%s" is missing a "down" method.';
 $lang['migration_invalid_filename']		= 'Migration "%s" has an invalid filename.';
 
-
 /* End of file migration_lang.php */
 /* Location: ./system/language/english/migration_lang.php */
\ No newline at end of file