Allow arbritrary creation of NotificationFilters when subscribing for notifications. Currently, only NotificationFilterSupport is suppported.

We should at least add the 2 other standard filters, AttributeChangeNotificationFilter & MBeanServerNotificationFilter

We'll do it through a factory mechanism, because each filter is initialized in a different way, eg:

<subscription-list>
<mbean name="JMImplementation:type=MBeanServerDelegate">
<filter factory="MBeanServerNotificationFilterFactory">
<objectname>bla bla </objectname>
</filter>
</mbean>
</subscription-list>