Allow hot deployment configuration from XBean style XML

• Testcase included:

  yes

Jetty does not currently support hot deployment when it is configured using an XBean configuration file. Greg Wilkins confirmed that this is true and indicated that the Jetty's ContextDeployer still needs to be annotated for configuration via XBean.

I'm attaching a patch that allows for hot deployment configuration via XBean. Below is an example of the XML configuration:

<deployers>
  <hotDeployer directory="/path/to/deploy" />
</deployers>