marvin: fixes for handling multiple phy. networks

zones do not qualify for vlans but phy networks should carry the
underlying vlan information. moving the vlan down to physical_network
in configGenerator.py.

also the sandbox example has been corrected to reflect this change
and includes an illustration of using traffic types with labels.

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
Reported-By: Marcus Sorenson <mlsorenson@apache.org>
devcloud-kvm: marvin deployment config generator for devcloud-kvm

The devcloud-kvm.py script will take the kvm.properties file to generate
an advanced zone configuration with two physical networks with traffic
labels for 'guest' and 'public' traffic going on 'eth0' and 'eth1'
respectively.

To generate config:
$ python devcloud-kvm.py -i kvm.properties -o devcloud-kvm-advanced.cfg

Signed-off-by: Prasanna Santhanam <tsp@apache.org>