title: Defining and using a Python class within a ROS catkin workspace
body: <p>I am running ROS Indigo. I have what should be a simple problem: I have a utility class in my package that I want to be callable from our scripts. It only needs to be called within our own package; I don't need it to be available to other ROS packages.</p>
  
  <p>I defined a class named HandControl in a file HandControl.py. All my attempts to import it, or use it without importing, fail. Where in the catkin workspace do I put it -- the root of the package, or in scripts? Do I need <code>__init.py__</code> anywhere (I have tried several places)?</p>