Cookbook names must pass a whitelist format

In particular, they may only contain letters, numbers, dashes or
underscores. No spaces allowed.
Change recently_created to recently_added

Both recently_created and recently_added termniology was being used
throughout the application for ordering cookbooks. This changes it to
only be recently_added as that's consistent with the UI.
Merge pull request #249 from opscode/whitelist-cookbook-name-characters

Cookbook names must pass a whitelist format
Merge pull request #252 from opscode/recently_created_to_recently_added

Change recently_created to recently_added
Remove use of RJS

RJS while useful can lead to security issues if implemented incorrectly
and can become brittle and add unnecessary complexity to a simple
problem. I'd like to address the problem at hand (making the application
feel more reactive) at more of an application level using something like
Turbolinks or PJAX. For now though I think having these actions as full
page reloads is fine and removes a bit of complexity and risk.
Don't store location and authenticate for update

store_location_then_authenticate_user! is more useful for follow and
unfollow actions. We'll want to handle authentication/authorization for
the update action a bit differently once oc-id is in place. Also remove
the flash message from the update action as it doesn't add a ton of value.
Merge pull request #253 from opscode/no_rjs

No RJS
More usable setup for the create account/sign in functionality.
Revise Cookbooks UI

- Format cookbook listing sort by options.
- Variable-ize the user dropdown colors.
- Add active state to category nav.
- Media query tweaks to category nav active state.
- Formatting adjustments to the cookbook urls buttons and form.
- Format platform icons on cookbook show.
- Some visual cleanup of the cookbook version dropdown on cookbook show.
- Provide margin above the cookbook listing on category and search
  result pages.
- Add bgcolor to category nav active state.
- Downcase and underscore category names in category listing in order to
  render correct css class.
Extract link_to_sorted_cookbooks helper