Font-Awesome 4.20

+added Font-Awesome 4.20
Font-Awesome link into header.php
Revert "Font-Awesome link into header.php"

This reverts commit 4f27444d7b12bc38fc1d143568f0b3c8987bdfbe.
Revert "Revert "Font-Awesome link into header.php""

This reverts commit 884953fcee20ea87a004fe7dbdfcaedbe2b9eb8a.