Velocity/drive command

[reed-adept]

Add a topic to accept some kind of velocity or driving command to rosarnl. See also #10 and [gdk].

[RobertBlakeAnderson]

Planning to do a pull request to add this soon.

@UTNuclearRobotics already has this feature and several others in our private fork. We're thinking of doing a series of pull requests soon to get our work into the main branch.

[reed-adept]

I've considered refactoring rosaria so that rosarnl can simply add to it. I'm not sure how to do it yet. The first step would probably be moving ArnlSystem into rosaria or into ARIA itself however.

[RobertBlakeAnderson]

Could maybe give RosArnlNode a private RosAriaNode member and construct it with the same nodehandle used by Arnl. Then have Arnl's Setup() and Publish() functions call the same from the Aria member. You'll also need to put RosAriaNode's definition in a RosAria.h so its main() doesn't get included.