added constants.php file and implemented constants for file system modes
diff --git a/user_guide/libraries/ftp.html b/user_guide/libraries/ftp.html
index 9e4af8b..0e577e9 100644
--- a/user_guide/libraries/ftp.html
+++ b/user_guide/libraries/ftp.html
@@ -258,7 +258,7 @@
 

 <code>

 // Creates a folder named "bar"<br />

-$this->ftp->mkdir('/public_html/foo/bar/', 0777);

+$this->ftp->mkdir('/public_html/foo/bar/', DIR_WRITE_MODE);

 </code>

 

 

@@ -268,7 +268,7 @@
 

 <code>

 // Chmod "bar" to 777<br />

-$this->ftp->chmod('/public_html/foo/bar/', 0777);

+$this->ftp->chmod('/public_html/foo/bar/', DIR_WRITE_MODE);

 </code>