Add output formatting for eunit assertions
Add stop function to rt_pb module
Add riak_cli dependency to rebar.config

Add riak_cli for use in formatting detailed test result output. The
riak_cli repo is currently private, but is planned to be opened very
soon so this dependency will be updated after that fact.
Eunit assertion failure handling and test output updates

Add handling and formatting of eunit assertion failures. Also improve
the test output by putting detailed test result information in a table
created using the riak_cli library.