added hack to document.tag.href to get drop data from grids

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2764 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
added PIMCORE_DOCUMENT_ROOT to view template helper

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2765 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
added applyGridEvents to object grid helper and object tags

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@2766 1f8fe7d8-47f0-464c-8d0a-336f4953ab05