- fix logout with multiple sessions asking for save

https://bugzilla.xfce.org/show_bug.cgi?id=5379
http://git.xfce.org/xfce/xfce4-session/patch/?id=9f3077be682355e1cd07e9a9463e76307292208c
- add systemd-logind support

initial Patch from arch linux / https://bugzilla.xfce.org/show_bug.cgi?id=8729
fedpra added suspend,hibernate support
- fix building with automake 1.13
- added patches from fedora
- fix building with automake 1.13
- rel 3