Use the default Xsession for kiosk mode

[broder]

Currently, the kiosk mode starts with a custom xinitrc, which overrides /etc/X11/Xsession. This costs us some nice things, including potentially useful things like registering a ConsoleKit? session (/etc/X11/Xsession.d/90consolekit)

We can bend a normal Xsession to do what we want by suppressing the gnome-panel and nautilus from launching, which we can do by setting the gconf key /desktop/gnome/session/required_components_list = [windowmanager]

Most of the applications in /etc/xdg/autostart should be harmless, if they even start at all for an unprivileged account without a panel. For those that are problematic, we can suppress them by creating files in ~kiosk@mit/.local/share/autostart that override the files in /etc/xdg/autostart.

This should make it much easier to start up the kiosk session, and would give us cleaner integration with the rest of the system.

[jdreed]

 https://github.com/mit-athena/lightdm-config/pull/3

[jdreed]

 https://github.com/mit-athena/kiosk/pull/1

[jdreed]

committed  5f18fa3f279dbe8c4f79ff9996fbaf2386c476c7 (Update to support the new kiosk mode) to master

[jdreed]

committed  541716dd88f815a1db5ea40d524a504084043013 (Major rewrite; use standard session codepath) to master