Add config option for hiding/filtering stats table

Fix #730. 

Putting this in but definitely looking for feedback on the approach.

Signed-off-by: Don Naegely <naegelyd@gmail.com>
I'm unclear as to how to get this option passed to the `CountCollection` class as the initial model is automatically created [here](https://github.com/cbmi/cilantro/blob/master/src/js/cilantro/session.js#L158-L164) and I'm not seeing a good way to include the option in the stats creation in order to pass it to the `CountCollection`. I could remove this from the model altogether and move the filtering to the `stats.CountList` view and pass the option into that view.