Consider removing fork dependencies

[fkrause98]

Riak Core is hosted on GitHub, and so are its dependencies, so we can't upload Riax to hex.pm for the time being.
We have some options for this:

• Upload Riak Core and its dependencies to hex.pm by ourselves. Some dependencies like Exometer are actually hosted on hex.pm, but Riak's upstream is using a fork of its own,
• Use a fork, like Riak Core Lite. This is actually a really good fork,
  and it's being used by AntidoteDB but it's lacking some features like Coverage Commands.