[Messenger] Browse functions in Messenger Support

[Louis Burroughs]

I added a browse() method to Messenger and implemented it in 
MessengerSupport. I use it mostly for testing.   It requires a few 
additional methods to MessengerSupport

MessengerSupport changes:

public Enumeration browse(Destination destination) throws JMSException {
    Session session = borrowSession();
    QueueBrowser browser = null;
    try {

        browser = borrowMessageBrowser(session, destination);
        return browser.getEnumeration();
    } finally {
        returnSession(session);
    }
}

##########Followed format of Message Producer / Message Consumer to allow 
caching someday##########

  /** @return a QueueBrowser for the given session and destination */
    protected QueueBrowser borrowMessageBrowser(
        Session session,
        Destination destination)
        throws JMSException {
        return createQueueBrowser(session, destination);
 
    }
############################################################################################

/** @return a new QueueBrowser for the given session and destination */
protected QueueBrowser createQueueBrowser(
    Session session,
    Destination destination)
    throws JMSException {
    if (isTopic(session)) {
        return null;
    } else {
        QueueSession queueSession = (QueueSession) session;
        return queueSession.createBrowser((Queue) destination);
    }
}