fix description and dependencies
Use base.qcow2 as image name if it is the first image.
Refactoring:
- Get rid of logging server, now there is a full
  Vmit server, and the vmit-ifup/down scripts request
  directly from the Vmit API
- Use Cheetah for running commands
- Add a Refcounted resource to automatically init the network
  no more vmit-network-setup