Bucket type support.

[daurnimator]

Amoung other things, riak 2.0 introduces bucket types.

Should be simple enough to add: just add a type field to options and in bucket creation

basho/riak#362

[bakins]

AFAIK, there aren't API's for this in Riak yet and the solution is still in flux.

[daurnimator]

See the above linked issue; furthermore the proto files have been updated on the develop branch: https://github.com/basho/riak_pb/tree/develop/src

[bakins]

I'm finally getting around to risk 2.0 support.