Added the clear kameleon command
Configure hostname and /etc/hosts in network_config microstep
Improved CLI user experience

- Kameleon shell has now a default bashrc (contrib/kameleo_bashrc.sh)
- Getting pretty prompt in interactive shell session
- Getting explicit recipe error messages during build
Removed lxc template
Getting checkpoints works with docker commit API
Docker template is almost ready

We need to fix build_appliance_from_docker step..