* Add an allocator which saves state in etcd
* Perform PortalIP allocation check on startup and periodically afterwards
Also expose methods in master for downstream components to handle IP allocation
/ master registration themselves.
* Defaults to v1beta1
* apiserver takes -storage_version which controls etcd storage version
and the version of the client used to connect to other apiservers
* Changed signature of client.New to add version parameter
* All controller code and component code prefers the oldest (most common)
server version