title: Complete example using Boost::Signals for C++ Eventing
body: <p>I’m aware of the tutorial at boost.org addressing this: 
  <a href="http://www.boost.org/doc/libs/1_38_0/doc/html/signals/tutorial.html" rel="noreferrer">Boost.org Signals Tutorial</a>, but the examples are not complete and somewhat over simplified.  The examples there don’t show the include files and some sections of the code are a little vague.</p>
  
  <p><strong>Here is what I need:</strong><br>
  ClassA raises multiple events/signals<br>
  ClassB subscribes to those events (Multiple classes may subscribe)  </p>
  
  <p>In my project I have a lower-level message handler class that raises events to a business class that does some processing of those messages and notifies the UI (wxFrames). I need to know how these all might get wired up (what order, who calls who, etc).</p>