Set up project to be able to perform dialyzer and docs mix tasks

[pcmarks]

It is desirable to be able to run both the dialyzer and docs mix tasks after every change to automata. They should be run before a PR for a change is requested.

To effect this, dialyxer and ex-doc needs to be added as dependencies to mix.ex

See issues #6, #7 and #9

This should probably be done earlier than later in the project's life. It is my understanding that in a couple of weeks (end of Feb?) there might be some significant changes to automata although this should not affect changing automatas dependencies.

Please read the online help for Elixir's dialyzer and docs. tasks.

[upstarter]

Thanks @pcmarks, I went ahead and added them. I will add a ticket to make them part of PR's also.