Support Node/NodeList as a valid name in all versions

Also refactor v1beta1/conversion_test.go `v1beta` -> `current` to allow
easier cut and paste of tests.
Internal rename api.Minion -> api.Node
Add 'nodes' everywhere 'minions' can be used in api / cli
Integration tests don't initialize with a client

Result is a 500 error if the client object is used
Rename client Minions->Nodes, select the correct path for v1beta3

Replaces the client public interface but leaves old references to "minions"
for a later refactor.  Selects the path "nodes" for v1beta3 and "minions"
for older versions.
Change podStatus from Nodes.List() -> Nodes.Get(name)

Retrieves a lot less data