Proofread Easy and Widgets Documentation

  * Move Easy index page to Easy documentation directory
  * Fix typos in Easy documentation
  * Move Widgets page inside its own folder
  * Fix typos in Widgets documentation
Add link to edit documentation pages on GitHub
Change edit_link to generate link to view file on GitHub

Direct link to edit a file on a GitHub repo, forces you
to fork that repo. It's better to let user decide whether
to fork and contribute or not.
Cleanup project

  * Remove unneeded files and assets
  * Cleanup comment hell
  * Organize css components
Proofread documentation

  * Proofread Authorization documentation
  * Proofread Easy documentation

(cherry picked from commit b0ccbf0450c0eade255baa423a32cf19a83fbae5)
Add note about possible double encoding of authorization code
Add missing stylesheet variable import statement
Fix company name in footer
Remove text-rendering property

It breaks font kerning and rendering in Mac Chrome.
Fix typo in feedspec for all flavors
Reorganize authorization index section
Reword authorization permissions section
Change authorization flows file format from DOS to Unix
Minor reword in authorization flows document
Change table format in analytics section
Add contribution guidelines