Update README to be concise, consistent & accurate

In an effort to create a more useable README, the following has been adjusted:

- use consistent markdown header syntax of #, ##, ###, ####, etc.
- make section headers semantically correct
- adjust language to be more consistent and readable
- wrap most content at 80 columns for readability and consistency
- move some content, like the roadmap, to the GitHub wiki
- update content to be accurate and up to date with the project
- remove the "to document" section
- add table of contents to the README

[skip ci]
Only import SCSS required for each file, remove settings.scss

To try and improve the performance of our styles compilation this
changes the application style sheets to only import the SCSS that is
required on a per file basis. This also removes the reliance on
settings.scss in favor of overriding foundation.css styles with
regular CSS overrides so we don't need to import as much.
Merge pull request #406 from opscode/scss-imports

SCSS Imports
Merge pull request #403 from opscode/readme_update

Update README to be concise, consistent & accurate
Increase the size of responsive header sizes.

This also adjusts some of the responsive padding for the beta banner.
Remove categories from cookbooks index

Since we're no longer exposing cookbook categories in the cookbooks
index UI there is no need to allow the cookbooks index to allow only
certain categories to be returned.
Merge pull request #411 from opscode/remove-categories-from-index

Remove categories from cookbooks index
adjusting language
Add data-equalizer to cookbook version show.

Ensure that the cookbook show and cookbook version show are the same views.
Merge pull request #410 from opscode/responsive_adjustments

Increase the size of responsive header sizes.
Merge pull request #412 from opscode/language-adjustments

Adjusting language
Upgrade to Rails 4.1.1 make adjustments for new API.
Update shoulda-matchers to fix minitest warnings.
Update titles and descriptions of various views.

This creates more accurate and descriptive meta titles and descriptions for the
the various views throughout Supermarket.
Merge pull request #413 from opscode/markup_updates

Markup updates
Rename permit matcher to permit_authorization

The permit matcher now conflicts with the shoulda permit matcher this
renames the permit matcher to permit_authorization to prevent this
conflict and to make intentions a bit more clear.
Use specific ref for shoulda-matchers

To prevent the validates_uniqueness matcher from raising a chef version
constraint error this pins shoulda-matchers at a commit where setting
default values for scopes was reverted, we can remove this ref once it's
released to rubygems.
adding printable CLAs
Move printable links to CLA forms.

Since the most likely use case for the printable CLA forms is when
someone is going to sign a CLA but needs to send over a copy to legal
this moves the printable CLA links to the CLA form view.
ignore the sitemap