improve UI for comparing steps

[stefanpenner]

Often it is useful to see how a specific pattern works given a specific amount of data as in many situations some cliff exists and one approach may be much worse then another.

I have found myself doing:

[100, 1000, 10000, 100000].forEach(function(n) {
  window.benchmarkSteps.push({
    name: 'do something (' + n + ')',
    description: ' test the of ' + n + 'xxxx somethings',
    fn: function() {
       // something based on N;
    }
  })
});

unfortunately the output becomes pretty gnarly, and it is hard to see the trends between the varying sizes of N.

Potential solution:

allow toggling visibility of: '.row.scrollable'
adjusting the styles to reduce step row height.