split up the tasks in the CheckSample task

Currently there are multiple scripts executed in the CheckSample task. It would be better for readability and modularity when these are split in individual tasks running in a loop. At least the download script and the retry script should be written as individual tasks. Also the print status script which runs in the UpdateStatusFile should be written in a task that runs prior to the Checksample tasks. The code would be more intuitive and linear that way.