Add batch size param to 1.3.1 release notes
Add batch size param to 1.3.1 release notes

biddyweb/riak,DavidAlphaFox/riak,basho/riak,GabrielNicolasAvellaneda/riak,yangchengjian/riak,xuejianhai/riak,authbox-lib/riak,amyvmiwei/riak,elkingtonmcb/riak,glickbot/riak,laurenrother/riak