First commit.

Allows a second ros environment (ROS Fuerte) in my chroot.
README.m
Multiple ros instances with isolated workspace. Self-managed roscore port. Minor chroot fixes.

Tested with host and chroots. But, for example, only one can obtain a kinect device
* Isolated workspace for each ROS Distro. By default ~/ros_workspace/<distro name>
Note that $HOME has been override for isolation, but rosdep init don't care it (TO-DO?)
* roscore port will be 11300 + rosversion (fuerte=8, indigo=10)
* Fix xterm warning
* Few improvements