allow discovery of CloudStackAdvancedZoneConnector

This pull request adds the binding classes and configuration necessary to discover the CloudStackAdvancedZoneConnector.  This resolves issue #175.

To configure this connector the cloud service name for the connector ("cloudstackadvancedzone") should be used rather than the class name.  Using the class name will still conflict with the other CloudStack connector because the last element of the package name is taken as the cloud service name; "cloudstack" in this case.

The discovery mechanism could be modified to use the full class name, if this is needed.  However, the class names are not very user friendly and simply moving to the cloud service names (and eventually dropping the class names entirely) seems to be a better option.
Actually this is needed because the method on the parent method refers to the value in the parent class, not in any subclasses.  I've modified the test cases to check this.  If you comment this out, the unit test will fail.
Another solution is to make the CLOUD_SERVICE_NAME into an instance variable.  In this case, the override wouldn't be necessary.