Update X11 switch tip.
call gnome-session correctly to start unity

Fix the startunity script to launch gnome-session.

This will fix many of the various bugs caused by gnome-session
not existing during a unity session.

gnome-session requires the DESKTOP_SESSION environment variable
to be set to launch properly. This script should also now be 
adaptable to work with gnome-shell and cinnamon.

Fixes #6
Install unity dependencies on quantal+

Adds gnome-session, ubuntu-settings, ubuntu-artwork, and nautilus
to the Unity target. Removes light-themes, which falls under
ubuntu artwork.
update /etc/timezone on enter-chroot

Sets /etc/timezone in the chroot when entering.

This fixes the clock in Unity, which uses /etc/timezone.
Symlink /etc/mtab to /proc/mounts to "fix" df. Fixes #253
Store the chroot name and link debian_chroot to it. Fixes #242
Make enter-chroot/unmount-chroot more resilient to shell selection.

Fixes #259.
Improve Debian compatibility. Fixes #257.
Fix bad speeling
Detect and set SHELL when running a command. Fixes #265.
Add GNOME target

Add a GNOME target to crouton, and factor out common code to
a reentrant wrapper around gnome-session.
Improvements to gnome-session-wrapper

Add optional session argument
Ensure style is consistent with the rest of crouton
Pass gnome and ubuntu as args to wrapper script
Merge pull request #281 from smibarber/gnome

Add GNOME target
Add mechanism for controlled restarting of the setup script.

This allows for the environment to be reset after bootstrapping takes place.
Don't hardcode dbus-daemon path. Thanks to @smibarber's #282.
Give GNOME a diet - use --minimal flag
Remove croutonticks, as it is no longer necessary.

https://gerrit.chromium.org/gerrit/#/c/45317/ has trickled down to stable.
Check if make_dev_usb has run; if so, enabling vboot bricks the system.
Fix croutoncycle on some systems.