New (nicer and bug-free) solution implemented for: PIMCORE-2130 - Pimcore displays the column names, not the labels of ObjectsMetadata

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@4571 1f8fe7d8-47f0-464c-8d0a-336f4953ab05