bugfix, thumbnail cleanup (video, image)

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3866 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
asset temporary file structure

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3867 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
build auto version (2953) ...

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3868 1f8fe7d8-47f0-464c-8d0a-336f4953ab05