Log Message:
www/contao45: add contao 4.5.1

Contao is an Open Source Content Management Framework developed by Leo Feyer
and distributed under the LGPL license.

Its open architecture allows everybody to extend the system to fit his
needs. Contao specializes in accessible websites and is accessbile
itself (front end and back end), rendering valid HTML5.

Contao 4.5 is fifth minor release of Contao 4 and it require PHP 7.1 and
MySQL 5.5.7 with InnoDB as default storage engine and utf8mb4 as default
charset.

Additionally, these new features from 4.5.

* Store the request token as cookie instead of in the session
* Improve the locale handling
* Support use of Symfony translator
* Add the insert tag flag for absolute URLs
* Allow to sort news items by date, headline or randomly
* Use the Symfony assets component for the Contao assets
* Display form fieldsets as wrappers in the back end view
* Support adding external JavaScripts to a page layout
* Add the "require an item" option to the site structure
* Support wildcards in the "iflng" and "ifnlng" insert tags
* Replace the back end "limit width" option with a \ 
"fullscreen" option
* Support sorting enclosures
* Add the teaser image as media:content in the RSS/Atom feeds
* Add roles and ARIA landmarks in the back end
* Add all the player options to the YouTube element
* Add the toggle icon of the parent record in parent view
* Add the "event address" field and update the microdata tags
* Use the Symfony security component for authentication

4.5.1 (2018/1/4)

* fixes issues with the Symfony security implementation.