Various CSS/copy tweaks

* Add text shadow to "Without Shoulda" and "With Shoulda"
* Turn "Get full instructions on GitHub" into a button
* Make headers small-caps
* Remove "thin style" font rendering, and turn off optimizeLegibility
  (as it was causing the small-caps headers to render funny)
* Set default styles for monospaced text: Droid Sans Mono, 0.875em
* Various copy tweaks
Flesh out examples section

* Make tab content area responsive
* Add new class to fit filename above code sample
* Tweaks to padding/margins
Convert tabs.js to CoffeeScript
Refactor vertical tabs JS

* Reorganize HTML so that links have an `href` of "#<tab name>" instead
  of a `rel` attribute
* Wrap tab content in a .tab-content class, and move id for tab name to
  the wrapper div
* Combining these together, when a tab is clicked, do not prevent
  default action on smaller screen sizes. The accordion tab (not the
  sidebar tab) will be visible and we want the browser to jump to the
  selected content div in this case.
Use Droid Sans Mono as monospace font
Prevent "With Shoulda" section from wrapping
Bring back font smoothing
Tweak example filename bg color