refactor(functional-tests): Modify the Cluster interface

* Add CreateMember, DestroyMember, Members, MemberCommand
* Make CreateMultiple a helper - CreateNClusterMembers
* Rename DestroyAll to Destroy
fix(functional-tests): Correctly identify zero machines
test(functional): Refactor smoke tests into specific cluster tests
Merge pull request #290 from bcwaldon/cluster-testing

Moar functional testing