use z-push and SabreDAV to sync calendar and contact when you use your mobile device

the z-push is used https://github.com/dupondje/PHP-Push-2

the webDAV is used https://github.com/evert/SabreDAV

the databse is used the baikal https://github.com/jeromeschneider/Baikal

update

update the z-push Authenticate from apache basic to digest