Minor Description
Currently if you use Libcloud naively inside a web application, it will re-auth on each individual request that as user makes through the browser.
It would be beneficial to allow OpenStack connection classes to be instantiated with an argument that allows them to use an existing authentication token.
Because the authentication process determines the base URL (by extracting the service catalog and individual service tenantIDs), specifying the authentication token (and so skipping authentication) on creating the driver should also require specifying the base URL.