Add the riak_kv_yessir_backend.erl storage manager for simulation purposes.
Add the riak_kv_yessir_backend.erl storage manager for simulation purposes.

%% @doc riak_kv_yessir_backend is a backend for benchmarking Riak without
%%      any disk I/O or RAM constraints.
%%
%% Riak: "Store this key/value pair."
%% Backend: "Yes, sir!"
%% Riak: "Get me that key/value pair."
%% Backend: "Yes, sir!"
%%
%% This backend uses zero disk resources and uses constant memory.
%%
%% * All put requests are immediately acknowledged 'ok'.  No
%%   data about the put request is stored.
%% * All get requests are fulfilled by creating a constant binary for
%%   the value.  No attempt is made to correlate get keys with
%%   previously-put keys or to correlate get values with previously-put
%%   values.
%%   - Get operation keys that are formatted in with the convention
%%     <<"integer.anything">> will use integer as the returned binary's
%%     Size.
%%
%% This backend is the Riak storage manager equivalent of:
%%
%% * cat > /dev/null
%% * cat < /dev/zero

andytill/riak_kv