Break dependency on cturtle for dry builds.

I've pulled in and tried to clean up the single_deb.py script from rosdeb.

I added a --fqdn option to single_deb.py, since my personal build farm requires it, and I've added the appropriate path to bring the repository fqdn down into the build script template, and updated the build script template to use single_deb.py from catkin-debs rather than from the system ROS install.