Hash Trees for use in Cluster Metadata · basho/riak_core@114cd4a

[ita-wasa]

This commit copies hashtree.erl from riak_kv (it will be removed in that repo). In addition, it adds a (temporary) dependency on eleveldb, which is used by hashtree.erl. hashtree_tree is intended to be used ephermerally (although there is no reason it cannot be persistent) but hashtree must first be