changes to limit quick start to only one IP addr per cluster
changes to support starting >1K VMs
remove extraneous changes for testing larger than 1 startups, leave
intact code changes for 'noext' feature, which limits the config to
one external ip addr for the entire cluster
Per Brian Dorsey's good suggestion, move external ip addr selection
from the google_cloud lib to the client app so that each demo can
decide the network config that works best. The Instance constructor
already has a way to set the desired network config at object
instantiation time so we'll use this in the quick start main.py code.
Merge branch 'master' of https://github.com/GoogleCloudPlatform/compute-appengine-demo-suite-python into noext
per Brian Dorsey's feedback, move network config logic out of the google_cloud
lib code and have the client code select the desired network config via the
already supported network_interfaces parameter to the Instance() constructor.
This makes a lot more sense than embedding demo-specific knowledge in the
general library code.
Merge pull request #14 from GoogleCloudPlatform/noext

Noext - limit clusters to one external IP addr attached to quick-start-0