Fix #2963

Changed all file permissions settings throught the framework
and the documentation.

Also added configuration settings for CI_Log and CI_Image_lib
diff --git a/application/config/constants.php b/application/config/constants.php
index 239fd46..c19f044 100644
--- a/application/config/constants.php
+++ b/application/config/constants.php
@@ -42,7 +42,7 @@
 define('FILE_READ_MODE', 0644);
 define('FILE_WRITE_MODE', 0666);
 define('DIR_READ_MODE', 0755);
-define('DIR_WRITE_MODE', 0777);
+define('DIR_WRITE_MODE', 0755);
 
 /*
 |--------------------------------------------------------------------------