add vshield_nat, add sample data for vshield_ha

added missing "enabled" option to create

updated property vnic to be ^[0-9]$

per randys code got original code of loop for the getter/setter methods

updated vshield_nat to remove ensure before block and cleanup

added fix for changing dnat to snat

used to_sym to be consistent
Merge pull request #25 from sholland/tb/nat

add vshield_nat, add sample data for vshield_ha
add datacenter, dvswitch methods
Merge pull request #28 from arguello/tb/vshield

add datacenter, dvswitch methods
update nat ha