Merge pull request #243 in ZP/z-push from feature/ZP-933-z-push-admin-could-expose-functionality to develop

* commit 'fc4f9d52':
  ZP-933 Now with file.
  ZP-933 Fixed wording in ZPushAdmin::ResyncFolder() if no folderid has been submitted for resynching, removed always false check, always strtolower() the searchFor as well.
  ZP-933 Added "gab" option for resync type, lookup gab folderid in configuration or device data, fixed resynching long and short folderids, to lookup folderids from backendIds stripdata should not unset backend2folderidCache.