catkin version of ParameterGenerator should output a more helpful message when invoked incorrectly

[esteve]

As seen in http://answers.ros.org/question/55647/dynamic_reconfigure-and-catkin-is-tutorial-correct/, ParameterGenerator should inform users to add their generator scripts to CMakeLists.txt and use the generate_dynamic_reconfigure_options() macro, instead of aborting abruptly.

[dirk-thomas]

I would say it should rather output which arguments are necessary to invoke it correctly.

[bajo]

This would be interesting for me as well. I try to use the dynamic reconfigure in a package which only contains one python node. It looks like the additional arguments that should be passed to the ParameterGenerator are used for cpp based files.