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/system/core/Output.php b/system/core/Output.php
index 238d223..de07125 100644
--- a/system/core/Output.php
+++ b/system/core/Output.php
@@ -606,7 +606,7 @@
 
 		if (is_int($result))
 		{
-			@chmod($cache_path, 0666);
+			chmod($cache_path, 0640);
 			log_message('debug', 'Cache file written: '.$cache_path);
 
 			// Send HTTP cache-control headers to browser to match file cache settings.