Replace Unity desktop with Gnome 3 on ubuntu 12.10

http://www.webupd8.org/2012/10/how-to-get-complete-gnome-3-desktop-in.html

1. Install the Ubuntu GNOME packages 

sudo apt-get install ubuntu-gnome-desktop ubuntu-gnome-default-settings

sudo dpkg-reconfigure gdm

sudo apt-get remove ubuntu-settings

2. Install missing GNOME 3 packages 

64 bit only

sudo apt-get install gnome-documents gnome-boxes

3. Upgrade GNOME Control Center, Nautilus, Totem 

and other GNOME 3 packages to version 3.6.x 

upgrade gnome control center 

sudo add-apt-repository ppa:gnome3-team/gnome3   

4. Remove overlay scrollbars 

sudo apt-get remove overlay-scrollbar*