“Improve” the surface of experiment.rb

This moves some methods out of the primary experiment.rb file, which makes it easier to read and understand probably, but adds indirection when working on the gem.

For people not working on the gem, this is an improvement. For people working on the gem, it's a bit of an indirection that might not be awesome.

Ultimately though, when look at the way experiment.rb ended up it feels like an overall improvement -- and those that want to, can dive into the mixins if they want to!