New security provider: jmsxuserid - use authentication information from activemq

Use the authentication information from ActiveMQ for callerid. 

This plugin enables the use of ActiveMQ provided "JMSXUserID" message header which is enabled with adding "populateJMSXUserID=true" to <broker ..> in activemq.xml.

I use it with the jaasCertificateAuthenticationPlugin which sets the username to the CN of the cert. Should work with any other jaasAuthentication plugin (ldap, ..)