[werkflow-user] correlation fixes

I've checked in some work-in-progress to get message correlation
working, at least to the point where the unit tests I'd written now
pass.

I also noticed that binding of messages to named attributes wasn't
working as I expected: given the following:

<transition id="transition two" type="and">
  <message id="myMsg" type="normal.msg">
    <java:correlator test="myMsg.payload.equals( bob )"/>
  </message>
  <task>
    <jelly:action>
      ${myMsg.touch()}
      case ${caseId}
      ...

I'd expect the received message to be bound to the 'myMsg' attribute
when executing both the correlator expression and when executing the
task. Up to now this has only been the case for the correlator, and the
action always got the message in the 'message' attribute. werkflow will
now bind the message to the named attribute in both the correlator and
the action.

-Mark.