Previous to this commit, the VNC password and listen address was defined
in the creation of a libvirt domain, whether a listen address or
password was specified or not. This commit, only adds the parameters if
they're specified, and not empty
* moved to using requests
* added vm nic/nics
* kept compatability with the existing interfaces
* moved util classes into util subdir
Signed-off-by: Amos Benari <abenari@redhat.com>