Adds more/less links to expand/contract long excerpts.

- There's no reason not to set all the properties of the bucket tabs
  in a single `d3.selectAll`
- Where code is self-documenting, remove excessive comments
- Some commenting style nitpicks (incomplete sentences should not end
  with a period)

 - remove .bartab
 - move .tab-pane CSS out of view code and into template
 - remove .tabbar in favor of just using .nav-tabs
 - remove bogus .right class on tab bar