@Override
    public void initialize(XMPPServer server) {
        super.initialize(server);
        this.server = server;
        userManager = server.getUserManager();
    }
Implements the TYPE_IQ vcard-temp protocol. Clients
use this protocol to set and retrieve the vCard information
associated with someone's account.
<p>
A 'get' query retrieves the vcard for the addressee.
A 'set' query sets the vcard information for the sender's account.
</p>
<p>
Currently an empty implementation to allow usage with normal
clients. Future implementation needed.
</p>
<h2>Assumptions</h2>
This handler assumes that the request is addressed to the server.
An appropriate TYPE_IQ tag matcher should be placed in front of this
one to route TYPE_IQ requests not addressed to the server to
another channel (probably for direct delivery to the recipient).
<h2>Warning</h2>
There should be a way of determining whether a session has
authorization to access this feature. I'm not sure it is a good
idea to do authorization in each handler. It would be nice if
the framework could assert authorization policies across channels.
<h2>Warning</h2>
I have noticed incompatibility between vCard XML used by Exodus and Psi.
There is a new vCard standard going through the JSF JEP process. We might
want to start either standardizing on clients (probably the most practical),
sending notices for non-conformance (useful),
or attempting to translate between client versions (not likely).

@author Iain Shigeoka
xmppserver/src/main/java/org/jivesoftware/openfire/handler/IQvCardHandler.java