Uniter Action(id string) API client/server

This commit adds the ability for Uniter clients to query Actions from
state.State by id.  The response includes a server error message if the
Action is not present on the state server.
This SetupTest is not necessary; the uniterSuite Setup/Teardown methods get called automatically.  You only need to explicitly include them when your actionSuite is composed of more than one other suite.