Update validateCsrf calls for Bolt 6

Update redactor-backend-extras.css

Merge pull request #34 from Filoz/patch-1

Replace Webmozart\PathUtil\ with Symfony\Component\Filesystem

Update redactor-backend-extras.css

Merge pull request #33 from Spomsoree/redactor-default-value

Use the default field option in the redactor field

Better syntax higlighting and wrapping.

Remove dependency on Deprecated `Webmozart\PathUtil\Path`

Updating Redactor to 3.5.2

Merge pull request #26 from bolt/feature/file-manager

New functionality: Add "File download" button

Update config.yaml