Use %placeholder for streching examples.
Added support for WOFF2 file types in the font-files helper function.

Change-Id: I76d2004eeace97b96826ab6d9d6df9242ba78d7e
OMG
Fix broken link.
Fix references to the old doc-src directory in the docs.
Replace cornell with linkedin on the homepage.
Show how to install the lastest prerelease.
Fix obsolete reference to VERSION.yml
Add missing image.
Update CHANGELOG
Grammar update.
Fix example
Document new project layout.
Blueprint is not an install option anymore.
homonyms.
Fixed issue #1766. Handles gradients without calling the compass mixins.
Mention the auto-required file in the extensions documentation.
Words
Fix wording.
Added a list to all index pages on the main reference page.