Added unit tests (in branch riak_core_3)

[pmenhart]

This could be useful for your readers: ExUnit now starts several slave nodes in a cluster (configured in config/test.exs). Ping, key/value, and coverage commands are executed. I also fixed a bug in CoverageFsm, and added a new coverage command NoSlides.Service.clear() to remove all keys from the store. A few remarks about running this project on Elixir 1.6.5 with Erlang 20.3.6 are in the Readme.

[bryanhuntesl]

Ooh that's cool. Nice work. @pmenhart gotta try this stuff out.

[pmenhart]

The latest commit works with riak_core_ng v3.1.1. Newer rebar3 is needed to avoid problems with gen_fsm_compat "missing erl_vsn". You can upgrade by running

mix local.rebar --force

[bryanhuntesl]

Nice pull request - interesting approach to booting tests +1