Reboot the box after desktop install.
Change thin option to remove packages.

The old thin idea led to a bit of a broken desktop and is too much work to get
right. So instead we install the full desktop and then strip it down.
Move back to thin for ROS base images.
Add link in docs.
Create a role for base images.
Move package removal into the base image role.
Use the official base from vagrant cloud.
Remove now unused thin vars.
Use new location for precise base
Add 32bit varients.
Xfce base image machine.
Merge pull request #93 from shadow-robot/f_ros_base

F ros base