basho/riak_kv — pull request #852 by andrewjstone (2014-02-20 22:27:25+00:00)
Title: Use iterator_refresh backend option for some folds

* Add iterator_refresh capability to riak_kv_elveldb_backend and
riak_kv_multi_backend
* Handle iterator_refresh option/capability for ?FOLD_REQs in
riak_kv_vnode
* support iterator_refresh option for AAE (riak_kv_index_hashtree)
* add riak_kv_vnode:fold/4
* return handoff fold options from handoff_started
* handoff_started has been modified to require this
* Get value of iterator_refresh from env. Default to true.