The should not depend on any turtlebot2 software.

I have broken out all of the common components into a new stack called` turtlebot_common` and `turtlebot2`. This way one can install either `turtlebot` or `turtlebot2` without requiring all of the software from the other. This also simplifies bringup somewhat as the `setup_t1.sh` and `setup_t2.sh` are no longer necessay, you may now simply call the roslaunch file for the specific robot.