Make sure to pass all variables defining the proper python version as found by
robotpkg, otherwise ros CMakeFiles may happily find python-3.2 and use it
instead of python<3, although this does not work in the end (at least ros-rx
does this and breaks on F17).

This is done in the common ros Makefile as this affects all packages.

The rx stack contains GUI-related tools for using ROS, including:

 . rxbag: ROS bag recording, playback and visualization

 . rxgraph: ROS graph visualization

 . rxplot: ROS topic data visualization

 . rxconsole: ROS/rosout logging output

The actionlib package provides a standardized interface for interfacing with
preemptible tasks. Examples of this include moving the base to a target
location, performing a laser scan and returning the resulting point cloud,
detecting the handle of a door, etc.

In any large ROS based system, there are cases when someone would like to send
a request to a node to perform some task, and also receive a reply to the
request. This can currently be achieved via ROS services.

In some cases, however, if the service takes a long time to execute, the user
might want the ability to cancel the request during execution or get periodic
feedback about how the request is progressing. The actionlib package provides
tools to create servers that execute long-running goals that can be
preempted. It also provides a client interface in order to send requests to the
server.