Add ovirtsdk.api based command-line utility

Added ovirt-cli.py, a command-line utility for interacting with the
ovirt api.  Supported API commands include:

 * test                Test connectivity to RHEVM server
 * vms.list            List available VMs
 * vms.add             Create VM from specified template
 * vm.delete           Delete VM
 * vm.add.nic          Add network adapter to specified VM
 * vm.start            Start specified VM
 * vm.stop             Stop specified VM
 * storagedomains.list List available Storage Domains
 * storagedomains.add  Add specified Storage Domain
 * storagedomains.attach
                       Attach specified Storage Domain
 * storagedomains.activate
                       Activate specified Storage Domain
 * storagedomains.deactivate
                       Deactivate specified Storage Domain
 * storagedomains.templates.list
                       List templates associated with a Storage Domains
 * storagedomains.templates.import
                       Import specified template into desired Storage Domains
 * templates.list      List available templates
 * clusters.list       List available clusters
 * hosts.list          List available hosts
 * datacenters.list    List available hosts

Refer to ovirt-cli.py --help for full list of commands and usage
information.