Upcoming Melodic release

[bmagyar]

Holding until this list is merged:

• [melodic] add missing pluginlib deps. #451
• Avoid nan command to be processed #283
• Added robot namespace to gui of rqt_joint_trajectory_controller #452

@seanyen @matthew-reynolds @ipa-mdl please comment/contribute to getting them merged/suggest others

[matthew-reynolds]

• WIP: Update CMakeLists.txt and package.xml ros_control#404 equivalent. Like [melodic] add missing pluginlib deps. #451, I want to do a thorough pass of the deps to make sure we're not missing anything in here after the ros_control cleanup.

[bmagyar]

The NaN check did not make the new release, thanks to everyone contributing!

ros/rosdistro#24002