Feature/revised/riak cli handoff status 1239

Implement "riak-admin handoff summary" and "riak-admin handoff details [--node=<node>] [--all]"
Throwing away extra list entries seems potentially suspect to me. If find_matching_outbound should only ever return one item, then we should only match on one item. If not, can we safely ignore extra entries? I'm wondering whether we might potentially end up showing the wrong inbound transfer type here. What if there are multiple outbound transfers that have the same target_node/target_partition/mod, but different types? (Not sure what mod means though, so maybe that rules out differing types?)