Aligns Search Results numbers and headers as separate columns #573.

[bwatson78]

1. _results_list.scss: realigns the header of each result as two columns that only collapse in mobile view.
2. _index_header.html.erb: groups the result header into a row div and the numbers and links into column divs.
3. sort_results_spec.rb: refactors the expectations of each test since the numbers and links are now separate elements.

[bwatson78]