[1.12.3] Prepare release announcement and version



git-svn-id: http://framework.zend.com/svn/framework/standard/branches/release-1.12@25289 44c647ce-9c0f-0410-b52a-842ac1e357ba
Version bump

1.12.4dev



git-svn-id: http://framework.zend.com/svn/framework/standard/branches/release-1.12@25292 44c647ce-9c0f-0410-b52a-842ac1e357ba