* commit '7cdb51e4':
  ZP-832 Run SyncCollections->CheckForChanges() stat comparing only on first run, improved comment.
  ZP-832 Add check if stats table can be loaded for shared users - log to INFO if that does not work, sync folders where no stat can be found only once a hour, include PR_CONTENT_COUNT, PR_CONTENT_UNREAD and PR_DELETED_MSG_COUNT into stat to reflect all kind of changes, SyncCollection->CheckForChanges() compares folderstats for changes when initiating, in case of error remove the folderstat to ensure folder is synchronized next Sync request, remove 'savestate' functionality as it is not used.
  ZP-833 Use http socket as default MAPI_SERVER.
  ZP-834 Remove SINK_FORCERECHECK configuration option and implementation.
  ZP-832 Request folder statistics from the backend and setup the exporter only if the stat indicate that the folder contains changes. Per default the statistics are disabled (backend has to enable them). If disabled, an exporter will be setup for each folder.
  ZP-832 Log GlobalWindow size override only once.
  ZP-818 Omit folder output on unchanged folders for AS 14.0 and higher.
  ZP-831 Combined - typo variable name. Released under the Affero GNU General Public License (AGPL) version 3.
  ZP-830 Combined; minor formatting fixes. Released under the Affero GNU General Public License (AGPL) version 3.
  ZP-829 CardDAV mappings for phone numbers. Released under the Affero GNU General Public License (AGPL) version 3.
  ZP-818 Supress collection containers if there are no changes for a folder, refactored code having the actual export and streaming of data in a private method.