title: simple example with spawnProcess
body: <p>I have a simple example:</p>
  
  <pre><code>subprocesses = {}
  
  class MyPP(protocol.ProcessProtocol):
      def processExited(self, reason):
          print "processExited, status %s" % (reason.value.exitCode,)
  
  
  class Test:
  
      def run(self):
          for i in range(0, max_processes):
              pp = MyPP()
              command = ['sleep','10']
              subprocess = reactor.spawnProcess(pp, command[0], command, {})
              subprocesses[subprocess.pid] = subprocess
              reactor.run()
  
  Test().run()
  </code></pre>
  
  <p>I want to delete from dictionary subprocesses element then subprocess is exited.  How to do it ?</p>