Hardlinks & static routes: implemented getNearestChildByPath() for hardlinks so that the behavior is similar do normal documents in the case "use childs from source" is enabled

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@4830 1f8fe7d8-47f0-464c-8d0a-336f4953ab05