Add support in api/v1.1redux for OOB consoles using VNC, refs #349.
More specifically:
 * Implement a new action ("console") for POST to /servers/id/action.
 * Extend api/servers.py to pass the Django request object to actions.
 * Import a version of the vncauthproxy control client under util/.
 * Extend the cloud command-line tool to support getting OOB console access.

Example json: {"console": {"type": "VNC"}}
Example XML:  <console type="VNC" />

To service the call, the API will contact a running vncauthproxy to set up a
time-limited port for VNC forwarding, where the client can connect.

This is WIP. Still missing:
 * A patched version of vncauthproxy.
 * Client-side (GUI) support for requesting an OOB console.