CFY-643 node state changes: removed reachable and riemann usage from the code; update_node API can now update node state as well as runtime properties; merged get_state and get_runtime_props params for get-node API into one; get-deployment-node API will now also return state_version for node when get_state parameter is used; node_state is now initialized to 'uninitialized' by default; fixed delete-deployment API to also accept deletion of deployment whose nodes are uninitialized (rather than deleted);  modified *_node_state to *_node_instance; added plugins.* into tests' setup.py