Add a utility function for marking APIs/usage as deprecated.
Add a utility function for marking APIs/usage as deprecated.

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