Paginate all, individual and company contributors

The contributors lists are getting a bit long and costly when rendering
the page so let's paginate them.
Add utf8-cleaner gem

If you make a request to Supermarket with invalid utf8 params it will
raise an exception because of a Rails bug explained here:
http://dev.mensfeld.pl/2014/03/rack-argument-error-invalid-byte-sequence-in-utf-8.
The utf8-cleaner gem sanitizes invalid utf8 strings preventing these
exceptions.
Refactor follow/unfollow button AJAX

Rather than re-rendering the entire view and manipulating the dom upon a
successful follow/unfollow request this moves the follow buttons (for
the show view and the partial) into a partial and renders them upon a
successful follow/unfollow then inserts the results into the dom.
Refactor User.authorized_contributors to return an AR Relation

So the result of User.authorized_contributors can be paginated using
Kaminari's SQL pagination refactor User.authorized_contributors to
return an ActiveRecord::Relation instead of an Array.
Merge pull request #625 from opscode/utf8

Add utf8-cleaner gem
Merge pull request #626 from opscode/follow-button-refactor

Refactor follow/unfollow button AJAX
Make copy for version downloads clearer

We currently display the number of downloads for the current version
being viewed so we should make the copy more clear to convey that.
Add delimiters for large download counts
Merge pull request #631 from opscode/cookbook-versions-count

Make copy for version downloads clearer
Merge pull request #624 from opscode/paginate-contributors

Paginate all, individual and company contributors
Add copy about deprecation to the modal.
Create the deprecate_search internal end-point

Create a unique search end-point in order for Cookbook deprecation select2
search to only return eligible cookbooks for deprecation. A cookbook is elgible
for deletion if it is not deprecated and not the cookbook to be deprecated.

Notes:

- the code in the controller should be moved into an instance method on cookbook
- the deprecation parts of the CookbooksController could be broken out into
  their own controller to KISS
- the enforcement of not replacing a cookbook w/ an already deprecated cookbook
  should be enforced at the Cookbook#deprecate level as well
Handle deprecation failure at the controller level

This could be improved by:

- improving Cookbook#deprecate to use record.save! and rescue from the error
- displaying the actual error
[WIP] Enforce deprecation failure if replacement is deprecated