Added support for Less-converting when Document_Service::render() is called

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2645 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
pimcore.helpers.showNotification - added option to pass a custom delay

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2646 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
PIMCORE-1920 - Asset ZIP Download: Add files using multiple processes (progress bar) to avoid memory issues on large folders

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2647 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
asset zip download: fixed download on root folder

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2648 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
fixed bug in Object_Abstract_Resource::getClasses(), failed on root folder

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2649 1f8fe7d8-47f0-464c-8d0a-336f4953ab05