Ensure libvirt connection is closed

- Still bugged in clients running libvirtd 0.9.8
Add sqlite3 as dependency
Use sqlite3 to store extended domain properties

- Return more information on '/domain/:name' from database
Permit shutdown and bootup of libvirt hosts

- Graceful shutdown on POST '/domain/:name/down'
- Force shutdown on POST '/domain/:name/down?force'
- Boot on POST '/domain/:name/up'