Without system cron: warning and a backup that moves on while the page is open (#13); progress of the database phase; Bin tab

- The admin page and backup:status warn when background jobs do not run on a
  system cron, or the cron stopped, with a link to how to set one up.
- Without a working system cron, the open admin page moves a running backup
  forward through /api/tick, a short step per poll.
- The database phase shows the tables dumped ("db: 47/183 tables"); a backup
  that has not moved for 15 minutes says it is waiting for background jobs.
- The trash of restore points is on a tab of its own, Bin.
- New screenshots; changelog and plan for 1.0.2.

appinfo/routes.php

@@ -24,6 +24,7 @@ return [
 		['name' => 'AdminApi#testTarget', 'url' => '/api/targets/{id}/test', 'verb' => 'POST'],
 		['name' => 'AdminApi#setTargetLimit', 'url' => '/api/targets/{id}/limit', 'verb' => 'PUT'],
 		['name' => 'AdminApi#startBackup', 'url' => '/api/backups', 'verb' => 'POST'],
+		['name' => 'AdminApi#tick', 'url' => '/api/tick', 'verb' => 'POST'],
 		['name' => 'AdminApi#setSchedule', 'url' => '/api/schedule', 'verb' => 'PUT'],
 		['name' => 'AdminApi#snapshots', 'url' => '/api/targets/{targetId}/snapshots', 'verb' => 'GET'],
 		['name' => 'AdminApi#browse', 'url' => '/api/targets/{targetId}/snapshots/{snapshotId}/browse', 'verb' => 'GET'],