added a simple way to add css classes to attribute rendersetting
code style and readded runonce.php
readded runonce.php
Merge pull request #393 from cogizz/feature/css-class-attribute-rendersetting

Feature css class attribute rendersetting
Merge branch 'contao3' into tng
Handle MetaModel dca loading differently.
Mark class ContaoController deprecated as it is subject to being phased out.

Replace all calls by contao-event-bindings.