Added a ros package as submodule.

I'm running through tutorials on ros #42 and thought that 
for ROS Integration it may be best to keep the ros components
in a submodule. This way it's possible to just clone the submodule into
a catkin workspace without adding all the extra SDP project stuff.

This commit should also reference #22 and #36.
Merge pull request #43 from mas-group/rosify

Added a ros package as submodule.