document tag pdf: enabled deferred thumbnailing again + use jpeg as tree preview images

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3027 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
wysiwyg editor: turn off CKEditor 4.1 ACF because this removes the custom pimcore_* attributes

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3028 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
build auto version ...

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3029 1f8fe7d8-47f0-464c-8d0a-336f4953ab05