Wrap backend output in various classes and add #akeeba-strapper.

Also refactored preRender(): return immediately when $platform->isCli()
Rename akeeba ID of F0FRenderJoomla and also add classes to F0FRenderJoomla3
Merge pull request #342 from jurianeven/feature/classes4

Wrap backend output in various classes and add #akeeba-strapper.