* Create directory.xml
* More Yealink fixes
-Spelling
-Wrong var
-Updated power_saving schema to be uniform across all devices to best written variable logic. - Good job whoever built it. IF YOU HAVE SET THIS UP IN THE PAST IN THE OLD FORMAT IT MAY BREAK. $yealink_powersave_* vars have been depreciated in favor of $yealink_ps_* since logic has been built to allow more with less total vars.
-Added some documentation