Add user sidebar to manage profile view.

This splits the user show sidebar into a partial that is then used on the
profile edit view. It updates the sidebar to display a different link based on
the controller (view for edit, manage for view). This makes the manage profile
view look similar to the user view.
Manage Profile view cleanup:
- Adds Foundation forms component to common.scss
- Removes padding and border from fieldsets
- Adds button formatting to various secondary functions on Manage Profile tab views
- Overrides default :focus background color and text color on search textfield to maintain search field design
- Adds paragraph to agreements tab under Manage Profile to maintain consistency
- Changes gravatar field to label to maintain text consistency on Edit Profile tab
Manage Profile - Collaborations changes:
- Adds descriptor paragraph for consistency
- Changes list to tabular format for consistency
- Changes Remove function to button
- Changes Remove function wording to 'Remove Myself as a Contributor'
Merge pull request #402 from opscode/manage_profile_update

Update the manage profile layout and styles
clean up supported platforms
Make cookbook following JS more explicit

Since the markup for the follow buttons is a bit different between the
cookbook show and the cookbook partial this separates the JS
functionality for updating the dom elements that should be updated after
a successful follow/unfollow. This also adds an additional feature spec
to test the follow button in the cookbook partial context.
Merge pull request #400 from opscode/supported-platform-cleanup

Supported platform cleanup
add uniqueness guarantees to SupportedPlatform
Merge pull request #405 from opscode/supported-platform-cleanup-part-2

Add uniqueness guarantees to SupportedPlatform
Merge pull request #404 from opscode/follow-button-fix

Make cookbook following JS more explicit
Update order of user nav to be user links first.

The links to view and manage the signed in user's profile seem a little more
important than those for signing a CLA. This is my proposal to move them above
the CLA links in the user nav.
Store supported platform legacy IDs on the platform join table
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]
Merge pull request #407 from opscode/nav_link_order

Update order of user nav to be user links first.
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 #408 from opscode/supported-platform-legacy-id

Store supported platform legacy IDs on the platform join table
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.