Success tally for the runner, and dumbed-down README.

Since you fixed _All of the Bugs™_ :kissing_heart:, and that now everything is running smoothly, I implemented the next crucial feature for a feature runner : *a tally*. 

I needed this, as when I ran the features the output was longer than the cache of my cli.

I threw in some additional explanations in the README, so make it more sexy for newcomers.

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BTW, how can we disable the DEBUG logger ?