Scripts for auto-generating robot packages

Initial PR for robot package generation scripts.  See package README for a quick tutorial.  Remaining items (not included in this PR) 
 * Python documentation
 * Wiki tutorials
iiuc, this generates names like `joint_1`, `joint_2`, etc. Do we want to handle mfgs that use letters to refer to joints differently? ie: the [MH5](https://github.com/ros-industrial/motoman/blob/hydro-devel/motoman_mh5_support/config/joint_names_mh5.yaml) has `joint_s`, `joint_l`, etc.