Reformatting IXR library
Update IXR lib from 1.61 to 1.7.4 + WP improvements

Update to latest Incutio XML-RPC Library
include also some Wordpress improvements
(see for more details the log of the lib as included in WP:
https://core.trac.wordpress.org/log/trunk/src/wp-includes/class-IXR.php )