Bump client version and riak_pb dep for Riak 1.4 features.
Bump client version and riak_pb dep for Riak 1.4 features.

basho/riak-python-client,GabrielNicolasAvellaneda/riak-python-client,basho/riak-python-client,basho/riak-python-client,bmess/riak-python-client,GabrielNicolasAvellaneda/riak-python-client,bmess/riak-python-client