ConfigurableFactory implementation to construct a JMSSender. There must be a 'queue'
property present to indicate what queue to send on. If a 'connectionfactory' property
is present it will be used to look up the JMS ConnectionFactory to use in JNDI, otherwise
the 'brokerurl' property will be used to construct an ActiveMQ factory pointing at the
given broker. If no brokerurl is present, then a default is used to point to localhost.